I work in a printing plant and we use solvents for the ink. I get ink all over my hands daily and one swipe with ethyl acetate or isopropyl acetate and its gone. We use it to thin the inks but also for cleaning up ink spills too. It takes care of grease, oil, varnish and ink in your case 'tude. The stuff we use can't be bought in stores but something close should work like mineral spirits, etc. Just a thought!