i have a few tiny little rust spots on car in a bunch of places.. I was wondering if i could just whip out the old sand paper, sand away the rust, then repaint over it with a little spray paint or something. Would this work? would i need some primer on there too? i just can't stand these little tiny spots on the front of my hood. Oh and also work for bigger rust spots.. about the size of a nickel? if this in fact would work in the first place Thanks.