PaulRon, that's hilarious! That's exactly what some of these are, a suit case full of old B&Ws from the 50s. I'd like to see some of yours! I think I'll start a thread to show old 50s B&Ws from the family. SYKES3
If they stuck together because of humidity, you might get lucky. What happens is the gelatin absorbs moisture, gets soft and then sticks to the surface of the other negative. Let them separate on their own, don't even tug on them a little.
That said, sometimes they aren't "glued" and can just be sheared apart, but if they stick at all, cool water at room temperature, (NOT COLD! Not hot!) soak until they come apart on their own. I've had some that seemed stuck, and when I applied sideways or twisting pressure, they just popped apart.
Hopefully all of yours are gelatin surface to the original backing. If they are face to face, I wouldn't have much hope.
Meanwhile if you peal them, or force them by prying, you'll get lines and bubbles in the surface, which won't go away.
I hope I explained the difference between pealing and sheering?
Photographs are less likely to be recovered, because the gelatin seeps into the other paper and bonds with it. Then there the issue of mold, which eats away at the surface of everything. However sometimes soaking can recover photos, if they didn't get fully wet. Freeze drying, in your homes frost free freezer, can sometimes work magic.
Slides are dead meat. If they get mildew, it eats the pictures. You can't wash them like negatives. Cleaning will often take off the surface in blotches. Kodachrome is worse than Ekatchrome.
This comes from having just about everything I owned go through a muddy stream overflowing. No slides were recoverable. Some B&W negatives survived. (most didn't) Color photos were slabs of paper mache. Some B&W photos, I washed and came apart.
Good Luck. Work slowly, and you should be alright. Do some small test batches so you can perfect your methods.