Preserving, I don't have a clue.
The baseball stands are a great idea but someone did give me another good idea for displaying. You can take a flat wooden board of some attractive wood that you like and drill 1/4" holes separated about 3" apart and place the balls on that. If you want you can drill them a little larger and even bevel the edges of the board and/or stain the wood or finish it in some other manner.
JoeyA