Staining on PSX stamps?

[dbs]

Does anyone have a problem with the top side of PSX stamps discoloring/turning black? (looks like black/brown smudges).
I live in Arizona, Land of the Dry Heat, so it's not a moisture problem. It doesn't seem to matter if the stamp has been used or not. Rubber side of the stamps is fine.
Can't seem to remove the staining, either.

[larue]

A lot of mine did the same thing. It looked like you put a dirty stamp on top if it, but I didn't.

[JBgreendawn]

I think that its just part of the wood it self, that that darker colors come out on some of the wood on the older ones. I have numberous ones with this... I try not to let it bug me.

[dbs]

Yes! It does look like you put a dirty stamp on it! Strange, huh?
I'm not sure that it is the darker color of the wood coming out in my case. I find it interesting, also, that the PSX stamps seem to be the only ones that have this "issue."
It only bothers me when I have PSX stamps I want to sell. The "smudges" aren't very attractive and some people think that it's from misuse of the stamp - staining, mold, or whatever - when that is not the case.

[snowcountry311]

i clean my stamp w/ a mix of very little bleach & water. rinse really well.