Originally Posted by MARTINSR
You could, but metal doesn't rust like that, the surrounding metal (within a quarter inch or so at least) is VERY thin.
If you see just small holes, it is rusting from the inside out and the back side is SHOT. Poke the hole with an awl or screw driver and you will see what I mean.
I agree with Brian, chances are if you hit it with the welder without checking the area around the hole you will most likely just burn a bigger hole into the sheet metal.