Can anyone tell me what to use on my 1956 Chevy wagon to remove surface rust without removing the original paint?
I would love to hear your ideas. Patty.

Is this a rust spot running down from a moulding or other trim?

If so, just use light rubbing compound to remove it.

If you are talking of bubbles of rust coming through the paint, then it is sand off the paint, acid treat the bare metal,prime and repaint.

One is easy and one is at the other end and extreme.

Where is the rust?

Yeah, I'm afraid the rust is little bubbles of rust coming from beneath. It isn't from the molding, not rusting water running down. It has been kept in Northern Michigan for two years in a 3 car garage that had no doors. Moisture!
The hood and roof have been repainted, but the sides are original paint. If you like real close you can see the specks of rust. If you step back, it still has alot of good paint. I just want to save it as long as I can before I have to repaint it. It is in a better garage now.

The best is to use a paint cleaner (use one with minimal abrasive material) and then a first quality wax to seal the surface.