Dear Donia,
How do I restore an old, damaged letter?
Q. Dear Donia,
A. Dear Jill,
It sounds like you have a wonderful letter!
You have a couple of options. First would be to consult a conservator about removing the tape to prevent it becoming brown and damaging the paper. You are lucky to be close to a great conservation center in Philadelphia. The folks at the Conservation Center for Art and Historic Artifacts are wonderful and would be able to help you preserve your letter. You can also leave it as is and just frame it.You will want to find a framer who knows how to do conservation framing so they know the techniques and materials to use. Be sure to talk to them about using a museum rag board for the matboard. Be sure to ask the framer to mount the page with Japanese tissue hinges using wheat starch paste. Finally, you will want to use UV blocking glass to protect the piece from excess light.
To help you understand some of these terms, see this leaflet from the Northeast Document Conservation Center.
I hope this helps!