I had heard about this stuff so went down to the dollar store and picked it up for $1.50. Put it to the test on my 222 which has rust stains in various places as well as the dark stain below the waterline. Got me a regular paint roller and rolled this stuff on the bottom of the boat. Waited about 3 minutes and hosed off. Took it right off. Heavy stained rust areas might take 2 or 3 coats but will remove it.
