Perhaps they could be xeroxed, and if necessary, glued to a thicker stock for
actual handling.

The New York State Library, if I remember properly from two decades ago, had
microfiched their older cards.

An article about library card catalogs, and that modern abomination, software
catalogs, in the New Yorker of a couple of years ago, noted that card files
generate information themselves: The more used and worn the cards, the more
useful they had been found by researchers over the decades.

Catalog cards dating back two (nearly, these days) are artifacts in
themselves.

"Just the fax, ma'am."
"To protect and preserve."
TGI Sgt. Joe Friday

David Formanek
Cyrus E. Dallin Art Museum
Arlington, Mass. 02476