I have a Williams Hayburners II that the leather clutches stick really badly causing all kinds of trouble with the chains that move the horses. Does anyone have any idea how to clean them up so they won't stick to the plastic disks?

I soak them in Neatsfoot and they must be so dirty with gunk that after a month they stuck right to the plastic gear. I have some leather I could try to make new ones from but the one that I did try to make came out pretty badly. I used a 1.25 inch hole saw bit. I think they were punched originally. I haven't come up with a solution for the smaller leather washers ones on the back side. I think they are .5 inches. Any ideas? It looks like the originals are still thick enough
to be used if I could get them clean.