by Paul Gasparola and Angela Brown
Professional Detailers Association
Nothing adds a finishing touch to a classic or modern automobile like beautiful leather upholstery. When properly cared for, leather upholstery will last far longer than other materials, and when premium hides are used, it will actually become more attractive with age. Cleaning and conditioning leather is similar to caring for you own skin. Leather not only receives the same abuse, but its natural porous texture allows these impurities to absorb directly into the surface. Leather is unquestionably the most delicate surface in an automobile and for years it was believed that saddle soap and clean leather were synonymous. What a surprise to discover that something as mundane as saddle soap could actually be detrimental to leather. Saddle soap is actually a mixture of soap and oil and was developed as the final step of leather tanning during the nineteenth century! Inherently alkaline, saddle soap not only does not clean; it can actually weaken and stain modern leather goods. Proper cleaning leather requires the removal of surface contaminants, not grinding them into the surface. This can be safely accomplished with the use of a pH-balanced cleaned formulated specifically for this purpose.
There are 2 types of leather: vat-dyed and sprayed on dyed. Immersing the hide in the dye does the coloring on the dyed leather. The color penetrates completely through the leather, whereas on sprayed-on leather the color is "painted" on. This produces a more even color, but some of the natural grain of the hide is lost and the overall life of the leather is diminished. A painted-on dye will wear off at the stress points. This may look like dirt build up, but looking close the dye will be gone. Most of the vat-dyed leather has came out of Europe. U.S. and Japanese manufacturers tend to stick to the sprayed on dyed leather. On the other hand, many late model U.S. car leather are coated with a protective plastic. The plastic, usually a PVC (polyvinylchloride), prevents penetration of any of the various leather cleaners and conditioners. Treat vinyl-coated leather exactly as you'd treat vinyl upholstery. Are leather cleaners/conditioners so essential for "raw", uncoated leather? Forget them. They can't get through the protective plastic barrier. To test whether your leather upholstery is "raw" or plastic-coated, apply a few drops of clean water to the leather. If the water is easily and quickly absorbed, the leather is uncoated; if the droplets aren't absorbed, the leather probably has a protective costing.
To safely clean leather you will need a neutral pH cleaner (between 4.5 and 7.5 pH) and a leather conditioner suitable for upholstery. Cleaning and conditioning leather upholstery is similar to bathing yourself out of a bucket on a camping trip. You need water to do the job, and you need to use the right amount of it Soaking is not required and can increase drying time a lot.
Five Steps to Clean Leather
Conditioning after cleaning is most effective because the cleaning process opens the leather pores, allowing the conditioner to penetrate deeper and quicker. Because leather interiors take small amounts of conditioner to properly care for them, premium high-quality products are your best choice. Apply your leather conditioner to a slightly damp cloth or sponge and wipe it onto the leather.
Dry older, neglected leather can benefit if the conditioner is gently massaged into the hide. Applying multiple light coats of conditioner is better than soaking the interior in one massive application when bringing back dry leather. The entire leather interior of the car should be treated and allowed 20 to 30 minutes to absorb the oils and preservatives. After this time, use a dry, clean towel to vigorously rub down all of the leather surface and stitch lines to remove any excess conditioner. After cleaning and conditioning, the interior should be allowed one to three hours to air dry, depending on the outside temperatures and humidity.
Why is it important to use leather cleaners versus all-purpose cleaners on leather interiors? To avoid stripping the color or altering the state of the leather while removing the surface oils that trap dirt, the cleaner must be the correct pH level made of non-alkaline cleaning agents. The pH level for leather is neutral, between 4.5 and 7.5. If the pH level of leather is elevated, such as by the use of a detergent like 409, with a high alkalinity, the life of the leather will be critically shortened as the bond between hide protein and its tanning agent becomes unstable and lost. Saddle soap was once thought to be good leather cleaner, however, due to its high amounts of oils, high pH (alkalinity) and its manner of use-rubbing it into the leather is ineffectual and damaging.
An effective cleaner will:
It is important to understand that each unit of pH measure is a unit of 10. So, if an ideal leather cleaner has a pH level of 5.5, and an all-purpose cleaner has a pH of 13, the all-purpose cleaner is actually 75 times too strong to use safely on leather.
© 2000 Paul Gasparola and Angela Brown (Member Profession Concourse Detailers Association)