Is there a proper way to remove rust from all areas possible
underneath an older vehicle so I can spray Zero Rust, which is
just a rust proof paint. Yesterday I purchased a 3" rough wire
brush for my 5" grinder and rough tested it last night on metal,
it sparks a lot and is difficult to control.
I have thought of sand paper, grinding wheels, but am not really
sure what is the way to go.

Any body out there who can lead me in a direction as to what
are the proper tools to remove rust. Also remember I will be
working underneath a vehicle.

Thanks in advance
Denny B