If you want to ensure that the balsa is really clean, blow it off with the air compressor, vacuum it with a horsehair end brush and then wipe it with a lint free cloth wetted with mineral siprits. You will be amazed at the balsa dust that comes off on the wetted rag after you have vacuumed it to death! The mineral spirits dries moderatly quickly and will not raise the grain like water or alcohol. It also removes any grease from your skin etc.