Clean candle molds
My hobby is candle casting and I've always had problems cleaning the Plexiglas molds, at least in those narrow shapes where you can not get in with your fingernail or scraper.
All attempts with hot hair dryer, shape in the freezer, etc. did not really help. Now I got from a cleaning lady (school) a bottle of basic cleaner, on the bottle is, "solves persistent wax and polymer coatings." The in the rinse water and the molds are like new!