Good thing you specified, or I'd probably get spanked by the site admin... Hmmm...
They make lube for them, bunch of different brands. Not always needed, but useful if ya gotta work it hard (my god this is sounding worse). I just grabbed an image of the first one that came up in a search. If you ever come up with a situation where you need and don't have, you can use soapy water, even rinse-less spray cleaners, just water as a last resort.
On that note, I'll be leaving now, before I sound even more like a dirty old man