WD-40 specialist rust remover soak dissolves rust quickly without harming surrounding parts, trim, gaskets or paint. the rust dissolver restores surfaces to bare metal without scraping, chipping or scrubbing. For light rust, leave parts in 1-3 hours and for heavy rust, leave parts in the rust removal solution overnight. This non-toxic and biodegradable formula is effective on small or large items that can be soaked.