How should I store old letters of varying sizes and ages?
Q. Dear Donia,
A. Dear Mary,
Great question! I would recommend keeping any fragile letters (I am guessing those from the late 19th and early 20th century) in their PVC-free sheet protectors and then storing them in an archival folder and then in a box. I usually like to limit fragile papers to about five per folder. For the more modern letters and envelopes, you can store them naked so to speak in folders and you can store approximately 10-15 pages per folder without having to worry. You might want to put a sheet of acid-free paper between each letter so they don't get mixed up and are easier to find when you want to but that is entirely up to you. An interleaving sheet will also help prevent damage between letters of different sizes.
This sounds like a fun project to tackle. Good luck!
P.S. If you must remove the labels, you can start simply by testing a corner with a small flat brush and a little (not a lot) water to see if it softens the adhesive at all. If it does, you know that you can work it of slowly with water. You can place a damp (not wet) towel over the label and let it work and them carefully lift the label with a frosting spatula. Do this slowly and if you encounter any resistance, place a new towel on and let it sit a bit more. Once removed, place it face down on a paper towel and gently roll (not rub) a cotton swab over the areas where there is still heavy adhesive to reduce this and let the label dry. They may not all come off perfectly in one go so be patient or you will rip the label.
I hope this helps.