I used to run the chemical warehouse for a major university so I know this works. Alcohol will work but it has to be very strong, not the kind you can purchase at Walmart. Usually a 95% (which is 190 proof) but it can also take out any other color and isn't the safest thing to work with. Test it first and do it in a well ventilated area. Actually I wouldn't want to use it on anything that a child would be handling. 409 will usually take it off non-porous surfaces, sometimes hairspray and constant blotting with fresh paper towels will take it out of fabric. Nothing will get Sharpie ink off paper. On books, I'd just get some pretty PERMANENT stickers to put over the writing. And I'd get the aggravating MIL a very fine point Sharpie.