KoatGuard Kill Scale is engineered to dissolve mild mill scale deposits. KoatGuard Kill Scale can be diluted up to 25% with water, and can be used in a pump sprayer or submersion tank Instructions: Leave KoatGuard Kill Scale on the metal's surface for up to 10 minutes.Once the mill scale has been removed, rinse with an alkaline solution.Then, rinse with clean water and dry the part.