Automotive Leather Upholstery

 

Note: This section of the site is in progress!

I will forewarn you, the topic of leather care is very confusing and, as such, is one of the most hotly contested areas of automotive detailing – just go to any detailing forum and do a search on ‘leather’, then sit back and get confused. I have spent countless hours reading, studying, testing products, and talking with individuals in the leather care industry in an effort to provide concise, honest, factual information. And, in the end, I am not even sure that I have a definitive answer as to the proper way to care for leather! I can, however, offer you what I feel is the best way to care for leather based on my experience.

If you have attempted to research leather care for yourself then I am sure you have come across your share of misleading, contradictory, information. The reasons for misinformation are many. First, there seems to be a lack of understanding of the various leather types. Second, there is (of course) marketing hype. And third, there is this yearning desire to ‘nourish’ leather with oils and conditioners. The types of leather used for automotive upholstery, however, have evolved just as automobiles have evolved and, in addition, some manufacturers use different types of leather upholstery. On top of this, companies that market leather care products are not always forthcoming as to why their products contain what they contain – and some even put ingredients into their products that do leather more harm than good.

The simple fact is that the majority of leather used in today’s automobiles is protected leather – this type of leather has a pigmented ‘color coat’ with a polyurethane/acrylate ‘top coat’ specifically designed for automotive applications. There are some well-respected proponents who state that protected leather needs to be conditioned with oils and others who state that it doesn’t and yet others who state that you simply can’t condition protected leather. A lot of debate and confusion has to do with the fact that not too long ago some leathers had to be cleaned with leather soap and then conditioned with certain oils – failure to condition the leather would lead to drying and cracking. Protected leather, however, does not need the same level of conditioning as the leathers of yesteryear…sure, it needs care, but not the same level of care. Protected leather needs to be kept clean, mildly conditioned, and protected. Trying to find a company, however, that sells cleaners, conditioners, and protectants (particularly water-based) that do NOT contain certain oils is very difficult.

With that said, let’s begin – in the end I hope that you walk away with a better appreciation for the type of leather that you have and a way to care for it so it looks nice and remains functional for a very long time.

Types of Leather: What type do you have?

First and foremost, in order to properly care for leather, it is essential to know the type of leather you’re dealing with.

It is probably not too instructive to learn the ins and outs of leather production and, for this reason, I am not going to bore you with the details. Suffice it to say that leather hides (typically from cattle) used for upholstery are currently chromium salt tanned (to preserve the hide), fat liquored (to provide softness, strength and flexibility (fats and oils are added)), and then dyed (to give them color). At this point, all leathers are more or less the same. Keep in mind that leather hides are often too thick for immediate use in automotive applications and, hence, the leather is split…the top is called ‘top-grain’ and the bottom is called ‘split’. From the point of view of detailing, however, whether it is top-grain or split is not really that important…what’s more important is how the leather is ‘finished’. For automotive applications the finish is perhaps the most important aspect of the leather manufacturing process as the finish affects many of the leather’s properties and the finish determines how you care for it.

In general, leather can be grouped into three major categories or types:

  • Type A = Aniline Leather
  • Type N = Nubuck Leather
  • Type P = Pigmented leather

That’s it…there are three types of leather: A, N and P. These types of leather have subtypes as well…but let’s stick with the major types. All leather begins as Type A, aniline. If it is sanded top-grain then it is Type N, Nubuck (sanded split is called Suede), and if it is painted with a pigment and then top-coated, it becomes Type P, pigmented.  That’s pretty simple! But how do you tell what type you are dealing with? For that we need a bit more detail.

There are four basic tests you can conduct to determine leather type: scratch, moisture, visual and tactile.

1. Scratch test: Find an inconspicuous ‘test’ area of the leather and lightly scratch the test area with your fingernail.

  • Type A and N leathers will scratch very easily and leave a lighter mark in the area of the scratch.
  • Type P leathers will not scratch easily and, hence, will not show a mark.

2. Moisture test: Find an inconspicuous ‘test’ area of the leather and apply a few drops of water to the test area.

  • Some Type A and Type N leathers will readily absorb the water. It should be noted that some Type A and Type N leathers may repel water for a time, but if rubbed, will absorb it. In addition, some of these leathers may also be treated to repel moisture.
  • Type P leathers will repel the water.

3. Visual test: View the entire piece of leather.

  • Type A and Type N leathers will have variations in hues and color. In addition, they will show scars, bites and other natural markings.
  • Type P leathers will have a uniform color and the natural markings will not be visible – they usually have an ‘embossed’ grain.

4. Tactile test: All leathers have what is referred to as a “tactile-feel” and a ‘hand’. ‘Hand’ refers to the suppleness of the leather and ‘tactile-feel’ is how leather surface feels to the touch.

  • Type A leather has a soft, warm, buttery feel and is usually supple.
  • Type N leather has a velvet-like texture.
  • Type P leather feels slick, similar to vinyl and is often less supple than Type A.

A word of caution before we move on:

Some automobile manufacturers have adopted the use of different types of leather on different parts of the seat – a common practice is to use leather for the seating surfaces and vinyl for the backs and sides. Another common practice is to use suede leather on the main seating surface with Type P leather for other surfaces. This complicates the leather care process. If you are in doubt as to the type of leather you have, refer to the owner’s manual that came with your car or ask your dealer.

Caring for Leather

Cleaning:

Hopefully you have been able to identify the type of leather you have…armed with this knowledge you can now move on to cleaning the leather. Before you start, you need to ask yourself a few questions: What level of cleaning is necessary to achieve your goals? What is the condition of the leather? Has it been taken care of recently? Is it a new car? These are important questions. Keep in mind that most over-the-counter leather cleaning products are formulated for ‘basic’ or ‘maintenance’ cleaning. These products are for newer cars or for leather that has been well taken care of – they are formulated to resolve minor surface soiling. Most likely, however, you will be doing “restorative” or “corrective” cleaning…you will not only be cleaning the leather of soiling, but you will be striping any pre-existing conditioners or protectants (even if you’re not doing this type of cleaning you might want to consider it as to provide a good base for moving forward).

Of the plethora of products on the market, which one do you choose? From my experience, products such as Leather Master’s Rapid S, Soft Cleaner, and Strong Cleaner are all basic/maintenance cleaners. In addition, some of the more popular leather cleaning products from Mothers, Meguiar’s, Griots, Lexol, Einszett, etc., are basic/maintenance cleaners. For corrective/restorative cleaning you will want to use products from, for example, Leatherique, The Leather Doctor, or Advanced Leather Solutions. Keep in mind that you get what you pay for…the corrective/restorative cleaners are going to cost more but will yield a better end result.

Step 1: Before using any products on your leather you must first remove any dry stuff…if you don’t then you risk scratching your leather. I strongly recommend using a soft-brush vacuum attachment to thoroughly vacuum the leather prior to cleaning with a solution-based product.

Step 2: Identify the type of leather using the above information as a guide. Keep in mind that 95% of leather used in automobiles is Type P. If it isn’t Type P then it is probably Type A Semi-Aniline.

Step 3: If you have Type P or Type A Semi-Aniline:

  • Method 1: Keeping with our intent to use the least aggressive method first, try to use lukewarm water and a mild soap along with a cotton or microfiber cloth to clean the leather. Surprisingly, this is what is recommended by automotive leather distributors (see, e.g. Eagle-Ottawa) and most owners’ manuals. Simply work up some suds and go over the surface with a soft cloth…then go over the surface again with another clean moist cloth to rinse off any soap film. While this is a recommended cleaning approach, it often doesn’t yield good results as the soiling is typically weeks to months old.
  • Method 2: If you don’t have luck with water and soap, you can move on to a pH-balanced leather cleaner – be sure to follow the manufacturer’s application instructions. All cleaners are different! Some basic cleaners that I recommend are: Einszett, Lexol, and Leather Masters. The method of application for these products is typically:
  1. Saturate a sponge in a bucket of lukewarm water.
  2. Squeeze the sponge so it is moist and put some product on the sponge.
  3. Work the product into the sponge until you have a foam to work with.
  4. Apply the foam to one panel at a time – this is important…work in small sections. Gently rub the sponge over the panel for agitation – in some cases you may have to use a soft-haired brush (such as a nail brush).
  5. Wipe the panel clean with a microfiber towel to remove the soap residue and suspended soils.
  6. Repeat steps 1-5 for the entire seat/section of leather. Keep in mind that those areas of your upholstery that get exposed to skin will require special attention.
  7. After you are finished wiping down the leather with the cleaner product you should buff the leather with a dry microfiber towel to remove any excess cleaner from the seams and cracks as well as dry the surface and prepare it for the conditioner.

One thing you may realize after trying the above two cleaning methods is that your leather still looks dirty…the soiling doesn’t just ‘fall’ off the leather surface because you are using a cleaner…cleaning leather is labor intensive. While I felt it necessary to at least recommend the two above methods, I can’t say that I strongly endorse them for situations where there is significant soiling or neglect. What I can assure you of is that if you use a corrective/restorative cleaner then you will achieve very good results. Products from Leatherique, The Leather Doctor, Advanced Leather Solutions, etc., will yield surprising results. Keep in mind that these products work as a ‘system’…there is a pre-defined process that you must follow to achieve the desired results.  We will demonstrate The Leather Doctor system in detail at the end.

(If you have determined that you have Type A Aniline Leather (pure, not protected) then you may need to use different products (see the Tips/Comments section below) because aniline leather is not finished – it does not have a protective top coat. While aniline leather is the least commonly used leather in automotive applications, there are still pH-balanced products available that will enable you to remove soiling – avoid using products formulated for finished leathers as they can harm the more delicate, non-coated leather hide.)

Step 4: After cleaning the leather it will be necessary to mildly condition it (and this is where a lot of the debate concerning leather care arises) and protect it. Conditioning is necessary to restore/replenish the leather’s moisture levels (even though it is top coated) and protection is necessary to help repel future soiling and moisture, aid in UV protection, and provide a ‘sliding’ surface.

Conditioning:

What is there to condition? Type P leather seats consist of leather hide that is painted and then top coated with a polyurethane/polyacrylic resin. Isn’t urethane hydrophobic (repels water)? And, if it’s hydrophobic, then won’t it repel any ‘conditioning’ oils just as it repels water? Furthermore, if it has a top coated then how do the oils introduced into the leather during the fat-liquoring process ‘get out’ of the leather over time? These are the types of questions that lead to debate and misinformation regarding leather care – and they are good questions. So, let’s address them.

Stating that non-absorbent top-coated leather can’t absorb water and oils is a correct statement…almost. BUT, and this is important, there are other ways for oils to get ‘into’ the leather. First, there are stitching holes. Second, the urethane coating is susceptible to wear, degradation, micro cracks, etc. Third, a lot of leather seats are perforated…they have little holes in them for breathability. In addition, in the late 1950’s production of microporous polyurethane coatings appeared. Since then, solid, porous polyurethane finishes (permeable finishes) have been achieved that allow for water and oil transfer into (and out of) the leather. Hence, the stitching holes, micro-cracks, urethane degradation, perforated holes, and permeable urethane finishes do actually allow some oils and water to penetrate into the leather. Even with these facts, most people will argue that the leather hide is inaccessible for the purposes of maintenance…but evidence proves otherwise. A brand new leather seat with a non-absorbent coating will not absorb oil and water if it has a non-absorbent finish. But, then again, a brand new leather seat does not need to be conditioned immediately. So, in some sense, this is a moot point. A leather seat that is a few months old (or perforated) will have holes, cracks, etc. that will allow some degree of oil penetration into the leather hide. In addition, quality conditioning products contain an ‘oil-in-water’ emulsion…this emulsion allows oil molecules to attain a size that is permeable to the finish – hence, the oil can penetrate into the leather. There is no doubt that introducing oils into protected leather is a challenging process…but what alternative is there? And if you are wondering how the oils evaporate from the leather in the first place consider the fact that the backside of the leather is not protected. If you could take the leather from the seat and condition it from the backside then that would be wonderful – but this is not usually an option. Still have doubts? Look at the stitching holes in leather that has aged some…you will most likely see tiny cracks around the stitching holes…this is exactly where the oils have evaporated over time leaving the leather dry and brittle.

Notice the microcracks forming at the stitching points on this leather seat.

The next obvious question is…”OK, I sort of believe you…now what do I use to condition Type P leather?” Well, first and foremost, don’t use conditioning products formulated for non-protected Type A leather on Type P protected leather –this a mistake. A lot of leather care product manufacturers put the same oils in their Type A leather care products as their Type P leather care products…and the oils in the Type A products simply sit on the surface of Type P leather and attract dust, dirt, etc. Likewise, don’t use conditioning products formulated for Type P protected leather on non-protected Type A leather unless the manufacturer states that it’s OK. Also, don’t use products that contain Neatsfoot oil, lanolin, mink oil, collagen, or aloe…these products do not have a place in the conditioning of Type P leather and most of them will leave a very greasy film on the surface. While it was easy to recommend ‘cleaning’ products, I can’t easily recommend ‘conditioning’ products. In order to properly condition Type P protected leather you will have to spend the extra money and utilize products from Leatherique, The Leather Doctor, Advanced Leather Solutions, etc…these are the companies that ‘understand’ leather – at least in my mind. Keeping your leather clean and conditioned will rejuvenate it, return the softness and flexibility that it once had, help it to resist cracking, and provide some level of wear resistance.

Method of application:

Conditioning leather is actually product specific as manufacturers have specific instructions for specific products. In what follows, I will document in detail how to condition (and clean) leather using some of the above mentioned products.

The Leather Doctor Kit

The semi-aniline kit from Leather Doctor is on of the best leather care kits on the market. In this section I will demonstrate the treatment of a leather seat using this kit (if you want to order a kit you will have to contact Richard Koh at Leather Doctor (info@leatherdoctor.com)…he is extremely knowledgeable and is a great resource for anyone who wants to learn about leather care). The Leather Doctor Kit comes with everything you will need to recondition/restore leather seats. It is a bit confusing at first as to how the products should be applied…but after going through the procedure once or twice it will make perfect sense. Richard Koh will always talk about leather in terms of its pH level…this is one way to approach leather care and it works well. The products in the kit are: Rinse 3.0, Cleaner 3.8, Prep 7.7,  Hydrator 3.3, Fatliquor 5.0, and Leather Scent B. The kit also comes with some small towels and brushes (that you will probably have to buy more of as the towels are only for one use). The numbers on the products refer to the pH level of the product…the kit seeks to, in the end, return the leather to its normal pH of ~4.0.

The Leather Doctor Kit has everything you need to care for automotive leather.

To demonstrate how to use the Leather Doctor Kit, I will go through the process on the rear seat of a Crown Victoria that has some damage. For purposes of demonstration, I removed the seat from the car – this is not necessary in practice. This is the seat prior to starting (the blue tape is only for demonstration):

This is the seat we will work on - notice the melted and dried blue crayon.

Step 1: The first thing you need to ensure is that there is no loose dirt on the leather – make sure you vacuum it well prior to beginning.

Step 2: The first product you are going to use is Cleaner 3.8. Simply spray the cleaner on the leather and agitate with the included brush. Then take a lint-free towel and wipe the product off…notice the soiling on the towel after this step! Make sure you clean the whole surface.

A.) Spray Cleaner 3.8 on the leather, B.) Agitate with a soft brush, and C.) Wipe clean with a lint-free cloth. D.) Notice the dirt!

Step 3: At this point, you might be able to go straight to using Rinse 3.0. BUT, in our case, the Cleaner 3.8 was not able to remove the dried crayon. Hence, we are going to use Prep 7.7. Prep 7.7 is an amazing product and I highly recommend it to remove the most stubborn soiling – to include dye transfer from clothing. Prep 7.7 can be left on the leather for a long time – in this step we let the Prep 7.7 stay on the surface for 30 minutes – but you can leave it on for a day if you need to. The process is simple…simply put some Prep 7.7 on the leather, move it around with a foam brush, and let it sit – you will have to experiment depending on the level of soiling.

A.) Prep 7.7, B.) Apply Prep 7.7 to the leather, C.) Move around with a foam brush, and D.) Make sure you get it into all the seams.

Step 4: After using Prep 7.7, I recommend that you repeat Step 2. Go ahead and use Cleaner 3.8 again as the Prep 7.7 will have lifted quite a bit of soiling that the initial use of Cleaner 3.8 didn’t get. Your actually going to use the Cleaner 3.8 to ‘clean’ the Prep 7.7 from the surface of the leather. This is what the seat looks like after the 4 steps!!!

This is what the leather seat looks like after the using the Cleaner and the Prep - quite amazing!!

Step 5: Now you are going to rinse the leather with Rinse 3.0. This is a very simple step – simply spray on, agitate with brush and wipe off!

A.) Spray Rinse 3.0 onto the leather surface, B.) Agitate with a brush and C.) Wipe off with a lint-free cloth.

Step 6: At this point, since we are doing a complete restorative process, we will proceed with Hydrator 3.3. This is a complicated step and requires some time. If you are simply doing a routine cleaning of your leather you can skip this step. To use Hydrator 3.3, you will first need to cover the leather with absorbent towels. Spray the towels and then cover with plastic to prevent the liquid from evaporating. You will want to leave this for an hour or so…again, if you are simply doing a routine cleaning, you can skip this step.

This step is a little involved. Lay down absorbent cloth, spray well, and let sit on surface to hydrate the leather.

Step 7: Now you will attempt to re-introduce fatliquor into the leather. This is simply step. Using Fatliquor 5.0, spray the surface, work it into the surface well using your hand, and then wipe off with a lint-free cloth. Make sure you work the fatliquor into the seams!

A.) Spray Fatliquor 5.0 onto the leather, B.) Work it into the leather, C.) Wipe off with a lint-free cloth, and D.) Apply Leather Scent B.

Step 8: The last step is to spray with Leather Scent B. After you spray the leather, wipe off any residue with a lint-free cloth. Leather Scent B will leave a very nice leather scent to the leather – just as it was when the leather was new!

That’s it! While this seems like a very long, labor intensive process, it really isn’t that bad – and the end result is truly amazing!

After using The Leather Doctor Kit, the results are amazing!

If you want to use the Leather Doctor Kit for routine maintenance of leather, you can simply clean with Cleaner 3.8, rinse with Rinse 3.0, and protect with Leather Scent B…it’s very simple and will do an excellent job at leaving your leather soft, supple, and beautiful!!

Tips/Comments

  • If you are trying to detail leather that is cracked due to severe neglect then keep in mind that the products mentioned in this section won’t enable you to ‘restore’ it – you will need have it repaired by a leather professional.
  • Depending on use and climate, leather seats should be cleaned, conditioned, and protected 3-4 times a year – dryer climates will require more frequent conditioning.
  • Most leather products on the market contain soaps, Neatsfoot oil, Hide foot oil, lanolin, aloe, mink oil, collagen, etc. These products have no place in automotive leather care! The use of these products on Type P and Type A semi-aniline leathers are not only un-necessary but, overtime, are detrimental. In addition, they will leave you with a slippery, greasy finish.
  • Ensure the cleaner you use is pH-balanced. High pH cleaners may cause premature aging and may damage the protective leather top coating with prolonged use.
  • Don’t allow grit, dirt or dust to build up to excessive levels as this gives way to an abrasive affect that will accelerate the degradation of the top-coat.
  • Areas that are in contact with your skin and head, for example arms rests, head rests, steering wheels etc. should be cleaned regularly, as perspiration will accelerate the degradation of the top-coat.
  • When cleaning leather, use mild pressure and, if needed, a soft nail brush – rubbing hard on the leather surface is not recommended.
  • Maintenance is key…wiping the surface with a damp cloth on a regular basis (every week/two weeks) is recommended to remove surface dust and dirt.
  • Never use saddle soap, furniture polish, oil, varnish, ammonia, or cleaning solvents.
  • Take a close look at the finish and don’t attempt to clean leather that is damaged!
  • If you still can’t identify the type of leather then read on…

Aniline Leather (Type A) gets its name from a colorless chemical called aniline – among other things, aniline is used in the manufacturing of dyes. Aniline leather, henceforth, is a natural leather that has been colored with a transparent aniline dye. Being a transparent dye, aniline leather has visible leather surface grain and natural leather markings (scars, cuts, etc). Pure aniline leathers are the most natural leathers and are not top coated – this type of leather is susceptible to spills and stains (it is absorbent leather). It is not typical to find pure aniline leather in today’s automobiles as it requires a great deal of care. Some high-end luxury vehicles may use this type of leather but water repellant is usually added to the leather to help in its durability – hence, a water test may not clue you in to this type of leather.

Semi-Aniline Leathers (Type A), like aniline leathers, are also colored with aniline dyes (and sometimes small amounts of pigment for color consistency) however they are protected. The top coat does not hide the natural leather markings but serves to protect the leather from spills and stains – semi-aniline leather is found in some automobiles (a common example being the Ford King Ranch). This type of leather will repel water like Type P leather but, unlike Type P leather, it will show natural leather markings (scars, cuts, natural surface grain, etc.) like aniline leather. This type of leather is the second-most common leather used for automotive upholstery after Type P.

Nubuck Leathers (Type N)start out as aniline and is sanded to create a velvet-like nap. It does not have a finish and is incredibly soft, sensitive, and absorbent. Type N is not often found in automotive applications and is easy to identify.

Pigmented Leather…also known as Pigmented/Protected/Top Coated/Painted Leathers (Type P) are the most common type of leather used in automobiles (~95% of automobile manufacturers use this type of leather). As such, this is probably the leather you have in your car. Type P leather is top-grain or corrected grain leather that is pigmented (painted) and has a finished top-coat. This type of leather offers a nice uniform look and color. In addition, it is quite durable – automotive leather upholstery needs to withstand changes in temperature, body oils, sweat, UV radiation, rubbing, spills, etc. Identifying this type of leather is fairly straightforward…one thing that you will notice quickly is the grain pattern…look closely at the leather and you will see that the grain is well-defined (it is an embossed grain). Also, you won’t notice natural leather markings (scars, cuts, etc.) as the pigment and protective finish hide such markings. Finally, the overall look of the leather will be semi-gloss or matte. Type P leather used in automotive applications is the most durable of ‘other’ types of pigmented leather (such as Napa leather, semi-aniline pigmented leather, and home/office pigmented leather).