You can talk to a taxidermist but what I have done for years is just let them air dry. If you do this make sure you get them in the form you want while they are still fresh as they will harden once dry.

I have added nothing to them and have lots I use for Hunter Education classes and some displays. Have even taken a rubber band tied down all toes except one which is now mounted as the Last Act of Defiance!

Can't show that here but is a good bar conversation plaque!

JW