archiving old portraits
I searched the forum but didn't find any info on preserving old portraits. I have a bunch of 5x7, 8x10 and 11x14 portraits from the 1920s through '60s that are all mounted or inserted into a cardboard type frame or folder. Does anyone know the best way to remove them or if it's best to leave them in the frames/folders? Some of the folders are falling apart. I'm guessing the frames/folders aren't acid-free so I thought it would be best to remove the photos but I'm trying to find out for sure.
Thanks for any help.