I have used spray carburator cleaner for cleaning
dried up grease off of
HP floppy drives. You might give it a try. Be carefull, it will dissolve
some plastics.
The more I use stuff based on D-Limonene the more I like it. Very powerfull
solvent, smells nice, doesn't eat my rubber gloves too badly. Common trade
name is I think Citrisolve, and its made out of citrus peels.