Well maybe if my wahs stayed at home all the time they would never get dirt in the pots from static or never go microphonic and broadcast the local hillbilly auctions! My stuff is clean and the pedal board is in a road case but once your out and about $h!+ happens. I think the tremonti wah by morely is the one that disengages when you lift off.
I too have played out for years and years, live in a dusty enviroment and have never had a problem with the wahs i use( standard GCB-95, Snarling Dogs Mold Spore, and 535). Does it sometimes get scratchy? Sure but rocking it back and forth a couple times fixes it most the time and a shot of air in the pot gets rid of anything else. Do you not use your wah very much? It could be that you just dont use it enough to clear it out. Also radio signals showing up in the mix can sometimes be an amp, power or even cable issue.
To the OP: Right now im doing a major wah search and so far my favorites are the MXR CAE, the standard GCB-95 and the Morley Dragon 2 wah for the wow function. I was really disapointed in the Clyde Deluxe, the one i got brand new barely worked and when it did sucked.
What sort of wah sound are you going for?