pinhole leak in neoprene waders

[Mr. 16 gauge]

Anyone here have a relatively easy way to find a pinhole leak in neoprene waders? I have tried the 'usual' method of putting them on and then wading in them, then trying to turn them inside out to find the leak......I still can't find it. It must be small, cause the waders aren't filling up, but I'm getting a pretty good spot over time.
.....and, before someone suggests it, it's NOT just persperation.....it is a definite leak. I have two pair that are leaking, and I really don't want to have to go out and buy another pair this fall.
Thanks in advance.............