I spray my aluminum bass boat to clean the lake stains off of it and it turns it clean and clear. Its a mild acid like product from NAPA. I noticed some white chaulky water stains on the FX and QX engine. While they were cold I sprayed them down and they turn nice and silver again. lightly rinsed them off with water and they look great. I rinsed with water about 5 min after the aluminum cleaner. After the water rinse I cranked them up and they dried off fine.