Originally Posted by Loose Gravel
What you describe could be either the film base itself decomposing or improper storage/processing or a combination of all these. If I were you I would leave them alone. Look for a state or local archive near you if possible and get them to offer advice on care and handling. I say this because WWII era negatives will be either Nitrate based or early acetate-based "safety film". In short, they're a PIA to handle and store, and someone in an archive could help you identify the film base and give you tips on storage.
So--leave them alone--brush off the dirt or any type of particles you can, but DO NOT rewet them. The emulsion becomes water soluble at a certain point with degrading nitrate negs. You'll ruin them, if you rewet them. If there's any mold in the gelatin, this could be pretty bad too. For the most part, the best thing to do is to either duplicate the negs or make prints & copy negs, and then store the originals *away* from everything else. Keep them cool & dry and let them breathe--because they both can offgass byproducts that will speed up their decay if trapped in a plastic sleeve or film can. The nitrate is highly flammable though and can damage other materials nearby.
1951 was about the last date of manufacture for Kodak nitrate film. They started phasing it out in the 30s. Pack film (sheets) and roll films were made up til the end. Cut sheets started to go out earlier. On acetate films--they say "Safety" on the edges. If it doesn't say Safety someplace, assume it's nitrate unless you can ID it otherwise. Thye can be hard to ID because records of manufacture of very spotty, and at first, they sorta decay the same way.
There was a survey done of negs in archives back in the mid 90s. According to a handout I have--the notch code for a pre-1949 Kodak sheet film on nitrate would have been a "V" first from the edge. From 1925-1949, they used a U in this place for Acetate base. This is Kodak though, ansco, defender, all those others are different.
Some good books are Kodak's "Conservation of Photography", the AASLH's (out of print) "Collection, Use and Care of Historical Photographs" ISBN 0-910050-21-X. or Siegfried Rempel's "Care of Photographs". ISBN 0-941130-48-7. You can also get handouts from suppliers like Gaylord Bros. or Hollinger that deal with caring and storing nitrate & acetate films.
Hope this helps, I might be able to dig out some links for you as well, your best bet is an archive though. Sounds like some neat images anyways, if there's an archive or historical society doing any kind of WWII history programs, they may be interested in the photos themselves. The time is now to get the good prints or copy negs though.