The Dawn/Vinegar solution removed soap scum so well I decided to try it on our nasty drip pans. Works better than anything else I've ever tried! Here's what I did. Fill sink with 1/2 cup Dawn Soap, 2 cups boiling vinegar, 8 cups boiling water and the rest just hot water from faucet. Soak for 30+ minutes. Scrub away the nasty!