Bet, why don't you Xerox the ones you want to use and then put the originals in a box with proper humidity, etc, only to be disturbed when you want to fondle them. I don't imagine there would be copyright problems sheet music that old.

My wife played in a "Palm Court" orchestra for a while and the organizer had the largest collection of that kind of music in Sydney (if not Australia). He kept it in folders on open shelves. He would handwrite out the parts from the originals for each musician. The sad thing was that his house was set afire by an arsonist and a lot of the music was lost. The fire was relatively trivial, and if it were stored in a more airtight environment it would have probably been saved.

Murray