I can only say, that stuff is just awesome. I ordered to manage rust on the car so that for the first time to sample a small amount. In various forums I read again and again how good and effective phosphoric acid is used as a rust converter And actually ... Have been so many parts edited it ... and it is very economical and acts quickly The rust I work roughly, they smear with phosphoric acid, leave on overnight and the next day the rust is gone ... The good thing is, phosphoric acid takes no paint (if something dripping beside it), no plastic parts or rubber. I have thus processed body parts and steel and iron beams ... The end result is always the same I will continue using it out