Body Work Tutorial

As far as fixing these rust spots, you have a few options.

1. Sand panel until they are gone (or as close as you can tell)
2. Grind panel with some sort of abrasive wheel (this may require you to do filler work if it is taking metal from the panel).
3. Chemically treat the area with an acid wash. (this is hazardous so be careful if this is your approach).
4. Treat with a rust "converter" Not my personal choice.

Have to ask about Rust converter and why you do not recommend it. My reason for asking is, when I painted my 37 Dodge Coupe, I had serious surface rust on the cowl vent, on the body around the cowl vent. I sanded the metal bare, and used a rustoleum rust converter on the cowl vent, the cowl, the front and back of the dash as well as a few other places. I did primer, and paint the car with a base coat, clear coat, and never had any sign of rust reappear or a sign that I had used a rust converter.