Help With Rattlesnake Skin!

Hello! I work in wildlife education, and was recently gifted two rattlesnake skins to use for programs. The skins appear to be in good shape. But, they are very dried out and hard. The woman who gave them to me said they were skinned, fleshed, and salted, but have been rolled up in her garage for a few years. They are dried in the rolled up position.

How can I rehydrate the skins to unroll them, and then what should I do with them to keep them looking glossy and pliable? Or, is it better to mount them flat to a board?

Any help is much appreciated!! I am very new to this