Hi, this is my first thread here and I want to get some insight on the best approach on cleaning socket terminals. At my high school we've got 8 source fours with 575w bulbs in them to light our stage and pit. After the source fours were installed, the old 360Qs were retired. Still lying around we have about 6 or 7 of them but mysteriously only have 3 socket assemblies and 1 working bulb. At the moment we would use them to spot our flag so that we don't have to run down and turn on the follow spot. The bulbs are a 750w and a 500w. The one 500w works alright but I suspect either the bulb is incorrect or it is in serious need of bench focusing. The 750w recently stopped working despite the fact that the filament looks almost brand new. I took the bulb out to inspect and it looks as though the terminals on the bulb have blackened and I suspect they aren't making contact. I'm willing to get a bulb or two to get them working but I want to make sure that if I do, I won't run into this problem again. So what can I do to clean out the sockets themselves and make sure they stay clean?