I've never used either POR15 or ZeroRust but they are encapsulating so I think that it works like a penetrant,pushing all of the air out of the pitting,taking away one ingredient in rust=air.When I do mine I'm gonna clean it up good but I'm not gonna get to picky with it.I'll probably use zerorust because it's alot safer,especially in a confined area like behind the dash.read the msds for por15,it's scary

http://www.por15.com/Portals/0/uploads/Files/pormsds.pdf

My truck


http://community.webshots.com/mypho...mp;albumID=551424330&security=ekZMUw