Use Rust Veto® 2212 following cleaning and heat treatment in hydrostatic testing tanks. This all-synthetic, aqueous-based rust preventive has the features of a non-nitrited chemical rust inhibitor. It contains no oil, which minimizes disposal problems, and no nitrites, which eliminates associated health hazards. This most-sold synthetic rust inhibitor maintains hard water stability, and it will not stain brass or copper. Use on ferrous and non-ferrous metals.