Rust Solvent Xxl. Frees seized bolts and nuts particularly quickly. Penetrates even the narrowest of openings. Infiltrates and dissolves rust. With rusted and corroded metal parts such as screws, bolts and other moving parts. Application: Spray a generous amount onto bolts or nuts to be loosened and as is usual with rust removers, allow to act for some time before loosening, depending on the corrosion formation. Repeat the process in extreme cases.