Working on the cargo area portion of the bed of the truck and I'm trying to get the rust off so I can put down some sort of liner. The front corners look as if the previous owner left leaves/grass there and moisture rusted it. It is not through but a thick surface rust as in picture one. I used the wheel in picture two to get it down to what you see in picture 3 and it worked pretty fast, just didn't get it all. Any suggestions on how to get rid of it other than keep going or using a wire wheel? I don't mind that the bed won't be smooth with the left over bumps from where the rust was I just don't want to paint over something that is going to allow the liner to peel up after a couple of years.