Rust removal via chemical means

(Muriatic) Hydrochloric acid is a lot faster. :D
The fumes are dangerous though, so you need a well ventilated area to use it.
It can be gotten at most any hardware store by the gallon jug, and is the same stuff they use for concrete and construction block cleaning.
I use it to remove the rust from our swamp cooler panels every year so we can repaint them because it not only removes the rust down to clean steel, but removes all the mineral deposits at the same time.