This specially formulated rust remover is a powerful, rust-fighting liquid created to meet the needs of auto restorers. It reaches even inaccessible areas, quickly dissolving iron oxide completely and leaving a zinc phosphate coating. Fast Etch can be sprayed, brushed, or used as a parts dip. It is non-toxic, non-flammable and reusable. This is not a primer. Treated surfaces should be wiped with PRE Painting Prep (10041 Z) or thinner before priming and painting.