iv'e aquired a few love taps from those rocks we like to drive over and scrape up against when it cant be avoided, and im wanting to tape off small sections and paint over for the winter so it dosnt get rusty as it sits outside all winter long. whats the best way to prep it out before i primer and paint (rattle can rustoleum paint and primer) do i need to go as far as 320 grit sandpaper or will some red scotch brite work ok to scuff it up, ive painted stuff before just curious the paint is actually still good on my truck clear coat and everything except were its been smashed and paint has started to chip off.