I've been collecting glass jars lately for a project I have in mind. Some of them are stamped with the expiry date etc on the glass itself, instead of on the lid. It annoyed me until I realised that I have some StazOn Cleaner that I bought when I bought my StazOn ink (the ink is a permanent solvent ink that stamps onto metal, glass, ceramics etc). Getting it off would be a problem, so I bought the cleaner as well.
Job well done! It cleans my stamps, and it cleans the ink off of glass jars :)