Cleaning Up Floor Rust

[Bierkan]

My truck has some ratty old carpet with pad in it. Lifting it up today to get a wrench on the body bolts, I discovered it's got quite a bit of surface rust. Probably from years of use and sitting, etc. I want to pull up the carpet, but what process is best to use to clean off the rust? After that I thought I'd prime it for now and later go over it with bed liner stuff.