I left a knife in for a few days; moderately rusted. Turned the blade an odd but 'kool' color. I left it that way...I liked it. Herb On Mon, Feb 21, 2011 at 4:13 AM, Linda Grunthaner <grunthaner at gmail.com>wrote: > Wow nice reviews on that Evapo-rust. What are the con's on this product > other than paint quickly. > Lin