I had to attach a piece of plastic 1 inch thick to a shoe sole to make it 1 inch taller. Why is not relevant.

After using this frankenshoe for 2 months I no longer need it, but the shoe sole is sticky.

I used isopropyl alcohol to rub it and removed a bit of junk, but part of the surface is still sticky. I applied more isopropyl and let it act for an hour. Still sticky.

What works for you?