I've got lovely black oily dust from my cheap hinges all over my doors and casings. Some are finished with poly, others are unfinished. What can I use to clean the black marks off without damaging the poly finish? What about the unstained pine? I'm starting cleaning the hinges (need recommendations for that too) and pins on the finished doors one at a time, in place, and using white lithium grease. I'll do the unfinished doors one at a time as I finish them.

Damp cloth doesn't quite get everything off (esp. in grooves) of the finished doors.

Thanks.