Steel wool of 0000 will work. There is one minor issue and that is it can leave small particles embedded in the surface. They can rust and cause issues if you decide to refinish. Copper wool doesn't have the same issues.
Something else that works very well is some Kroil and a stick of white chalk to rub off the rust. That is what I use to remove rust from Damascus barrels with out damaging the original delicate pattern.
These barrels were completely covered in a layer of rust. This is how they look after the Kroil and chalk treatment.
