the best polish i have found is g3 polishing compound its what body shops use, i had washed my car and a m8 saw it the day i had washed it (about 2 weeks ago) last thursday i used some g3 on 1 side, i hadnt botherd washing the rest of it, and a m8 saw and thought i had spent hours washing and waxing it, its that good lol, but its strong stuff and will burn the paint unless u keep the paint damp, there is a less violent version called g10 and its a mild polish, slightly stronger than t cut or any other polish you can buy in shops, and that will work whonders also.... other option is some 4000 grade wet sandpaper but i wouldnt recomend that unless you REAAALLLY know what you are doing