Typically, a little longer than normal wash processes. 20-30 minutes in an immersion or soak process with a high concentration of a citric acid product wouldn’t be surprising. However, it is important to make sure that ALL rust is removed. So, the first time you de-rust in an aqueous application will be more of a “guess and check”. The time will depend on many variables including amount of rust, type of part, part geometry, etc.