how to get rid of rust

I am starting restoring my 70 bug. The question is there is some rust ,
mostly surface, on the rain gutter. the body shop that painted it the first
time did not pain the car correctly so the rust has blistered the pain and
was wondering how I should go at the rust? I do know that there is some
under the pinch weld (between the side panel and the roof pane) but how
should I get rid of it? I really do not want to have to cut off the rain
gutter and weld in a new one if I can avoid it.
George