I tested this product in the engine room of a WWII battleship against 70 years of rust and dirt. I was amazed at the performance, especially when compared to a product like the WD40. It worked its way through caked paint, rust, and even rubber gaskets to loosen threads. No hammers, heat, or striking tools were required. (Check out the picture to see what you can do with it.) This product was particularly useful for brass clasps as they are much more prone to chipping. I never thought I'd say that, but PB hit his opponent.