Originally Posted by swamp2
As an aside I am still unclear and interested in what exactly gets removed and damaged in a typical automotive leather product by extreme abrasion. Is there really something on the leather in analogous to a clear coat on paint?
I don't want to get into the ME discussion, but I can provide some info on this point.
Most automotive leathers (regardless of marketing name) are "coated" or "protected." What this means is that after the leather is tanned and dyed for color the surface is coated with a protective chemical. This is analogous to the clearcoat on modern paints. The formula of the coating can be changed in order to alter the sheen of the finished leather (from matte to glossy) much in the same way that the formula of paint clearcoat can be altered to change the surface finish.
The benefit of this process is that it makes the leather resistant to water and dirt build-up. In a quality leather the material still feels soft to the touch and has the high-quality look, feel, and smell that we've all come to expect.
Trying to figure out if a leather is coated/protected or not?? Put a drop of water on the surface (use a hidden spot) and see what happens. If the leather is coated then the drop will just sit there and eventually evaporate (I'd recommend wiping it off after your curiosity is satisfied). If the leather isn't coated then the water will very quickly absorb into the leather (and ultimately stain it).
Almost all automotive leathers in use today are coated. The exceptions are the ultra high end (Rolls, Bentley, etc) and, oddly, the Ford King Ranch Edition trucks.
Coated leathers can be cleaned using any number of products including a mild all purpose cleaner (like 1Z Blitz). I've gotten excellent results cleaning leathers using Blitz or 1Z Plastik deep clean. After cleaning I follow with a conditioner that is designed for coated leathers. This isn't a typical hide food style conditioner (as you aren't doing anything to the leather itself) rather it's a protectant for the coating on the leather.... much in the same way that wax protects your paint's clearcoat. Most good leather conditioners are designed to provide this protection without making the surface glossy. I typically use 1Z Leather Conditioner and find it works great on my BMWs.
Over time leather is getting shiny from the oils and contaminates from your body and clothing getting stuck to the leather surface. Although most conditioners have some cleaning properties often they aren't strong enough. That's why a gentle APC works wonders.
As for the ME... I don't doubt its effectiveness, but it is an abrasive. It may not feel that way to the touch, but at a microscopic level it does break down the coating on the leather. Look at it this way.... Meguiar's M105 Ultra Cut Compound doesn't feel rough to the touch, but use it too much on your paint and you won't have any clearcoat left.