Here’s a little snippet on the slicking solution from Sara Hagel:
It works on every type of leather I’ve tried it on. I personally use it on veg (saddle leather and English bridle), waxy veg (harness), veg retan (latigo), all types of chrome tan, alum tan (also called Indian tan), and even blue crust (horn wrap material). My process is to put a very small amount on the edge (I don’t want it on any of the unedged parts) and then rub briskly with a canvas. A number of my customers use a burnishing wheel of one type or another and say it works equally well with that method. It won’t block dye, so if you dye edges, you can dye after burnishing. Once my edge is smooth, I apply some form of acrylic topcoat. Bee Natural RTC and Weaver Tuff Coat are my favorites.