I got a can of Deoxit and worked a possessed 7300/200 over with it. I hit every slot, then set something in and out of the slot while it was wet. All contacts cleaned and dried.
The G3 333mhz (running at 350mhz) CPU upgrade is now working flawlessly! It boots up just fine and the Powerlogix software is enabling the cache! It has 3.5ns cache chips, which means they should run at 166mhz, but bumping them from the stock 117mhz to 140mhz resulted in a hard lock a couple minutes later. I also have an old OrangeMicro USB + FW card that is now working fine too, though at least one of those NIB OS 9 compatible cards still isn't working at all. It's recognized as two USB cards in ASP, but the LED on a thumbdrive doesn't even blink on when plugged in. Usually it'll at least blip on for a second, then stay dark when the cards don't work. I also have the Mac Radeon 7000 working. Oddly enough, it only started working when I installed it, booted from the onboard video, installed the 2002 ATI drivers, and then rebooted with the monitor attached to the card. Some kind of NVRAM sorcery? And if so, would it survive a PRAM zap/NVRAM reset?
Oh well, at least this has solved some problems. I'll probably work over all the other machines as well just to be sure everything is nice and squeaky clean. I'm definitely a believer in the power of Deoxit!