I've been repurposing the tops of leather riding boots, no longer useful for wearing. There is a 5" leather band on the inside top of the boots, and 1" leather down the sides of the stitching in the backs. I like the unlined boots as they allow to have better contact on the horse for riding/jumping. The image is of my custom Vogel boots, showing the inside singing which came off easily, however my partially lined French Waxed Calf custom Dehners are more of a challenge. The leather is a bit heavier, and I'm having difficulty removing the inside liner. inside vogel Can the tops of the black boots be soaked in water/glycerine? I did not want to use acetone because I do not want to dry out the leather I'm going to be repurposing. (I carefully removed all the stitching threads and can remove ripples from the brown boots so I can use them for projects).
You can soak leather in water. It's a very common step in leather working, especially to decorate the leather with punches. To avoid water stains you should always soak the entire piece of leather.
If the boots were made with traditional materials, the glue is a water-soluble organic glue (there are several different types of glue, but the traditional ones are almost all water soluble). Soaking in warm water can help dissolve the glue faster. However, several modern glues or contact cements are not water soluble, so if the leather piece doesn't detach after a few hours, you can only scrape it off, which probably damages the leather.
Soaking leather in any type of alcohol (ethanol, isopropyl, acetone, etc) dries them out and makes them brittle. Never apply acetone to leather, don't even wipe the leather with acetone! Acetone destroys the tanning components which are the big difference between a raw hide and leather. Leather treated with acetone even once will crack and rip and simply be destroyed.
If you want your boot leather to be softer and more pliable, you can add 1 part glycerin to 2 parts soaking water. That acts like a moisturizer for the leather, but prolongs the drying time.