I'm fixing my windows and while I've got all the regulators out I'd like to clean them. I know to use white lithium grease to lubricate. But what's the best thing to use before that, to clean things up?

 

If you don't have access to a parts washer, scrape them as clean as possible and spray them with brake cleaner.

One critical spot is to remove the riser rollers, and polish the studs to make sure the rollers turn easily.