text: why does rubbing alchohol remove permanent ink from plastic surfaces but whiskey doesn't?   water content in whiskey is too high. even cask strength whiskey rarely exceeds 60%, while rubbing spirit will be 80%-95% alcohol.  alcohol acts as a lipophile (fat-loving) solvent only when there isn't too much water to emphasize its dipol nature. permanent markers use lipophile solvents and don't solve in water.