MEK only for the stubbornist of goopy stick-on gunk. I've read about certain window cleaners for cars that are 'specially formulated' to cut road grime, suggesting that it is too tough for Windex. yes, I use Windex on the inside, but I don't remember when was the last time I did the inside of the Zed. When I first got my Escort, I drove to work early each morning, and every few months, the inside of the windscreen fogged up from the shampoo stuff drying off my wet hair! Carl- Never MEK on paint or rubber. That's why I use mineral spirits. Takes off the gunk, glue & wax. Oh- I use plain newspaper for a rag, too. Fancy shop towels waste your money, kitchen towels are too cheap. Uncolored, unhandled newspapers are guaranteed clean & hold up to the liquids, they're (practically) free, and they get tossed anyway. thx