A little late to the party but an easy way to remove the hardened Ink is Ez off oven cleaner. The company introduced a Flatbed Duplicator in Just power it up and try to get some 8. Otherwise, a lot of soaking, scraping and chipping. These machines are what we now call offset duplicators or printing presses.
Soak, scrape, wipe, repeat.
AB Dick 9810 Printing Press
InPresstek, Inc. I never thought of outfitting such a press with photopolymer plates but it seems like a great idea! Aaron David on 22 Dec 14 Run This Off on the Mimeo". I would run the press without anything in it- no plate, no ink, just a blanket if you can figure how to install- and feed some paper through it.