Does anyone have any safe suggestions for cleaning the backs of old photos(from ca. 1910)?? These have writing on the backs of them, and they were at one time glued onto what is probably a page from and old photo album.? I can get the black paper off some places, and I can see through the glue, but there are some areas that the black paper is really adheared to the glue.? Is there something I can put on the paper to lightly disolve it without it going through to the other side of the photo? I've tried lightly scrapeing it but at times accidently get some of the lettering.? Thanks a lot!? Janine