Rust Buster As a DIY'er, Rust Buster is one of my favorite products because it REALLY works. I came across it by accident at a small tractor supply store in southern Missouri. The product typically works instantly, but on heavy-duty applications, I like to apply a little (or a lot) on a rusted or frozen bolt or car part, tap the part lightly to aid penetration, and wait. After a few minutes, rusted bolts, screws, shafts, piping, any types of "frozen" connections and assemblies will now break loose. I have tried a variety of other loosening products, but they tend to use heavier oils that don't penetrate as well. Smaller hardware stores, and farm supply stores will probably stock it.