Hello all! Just thought I'd share my recent experiences - of course all my experiences with SKs are recent because I never had one until a year ago. Anyway, I recently cleaned mine up. I used the method that member checker758 posted on the first page of this thread to pop out the grease caps. I sprayed some WD40 around the caps and let it soak in a minute, then blasted it with the icy spray of an upside down compressed air can (for blowing the dust off your computer keyboard), then gave it a good whack on a 2x4 that was laying on my work table. One of them popped out on the first whack, the other took 2 or 3 whacks. All in all, it was quite easy.
As to the squeakiness, I believe - at least in my case - it's coming from the metal linkage between the footboard and the cam. I am also using a WFL flat hihat stand with the same metal link between the footboard and pull rod - it's squeaky too. Anyway, I was recently playing a low-volume restaurant gig and heard a lot of squeaking as I was opening and closing the hihats. I didn't have any grease or WD40 with me, so I asked the kitchen for about a spoonful of cooking oil in a cup. I put a few drops at the hinge points and didn't hear any more squeaking for the rest of the night.
So, maybe pay a little attention to the linkage if you're trying to quiet your SK.
Lynn