Denny,
It is certainly meant to work fast. It will also remove the thickest, most stubborn rust. This is really where it shines, no pun intended! Keeping in mind that this is a non-toxic, non-hazardous fluid that does not depend on strong acids or bases to do it's job!
By all means, experiment w/it first, wherever possible, as every situation will vary. I do believe that it will greatly benefit anyone wanting to derust doors or any other surface that is relatively inaccessible.
Have you visited our website to look @ the pictures?
If you need any other advice, We will be glad to help.
Regards, Lee
