For those that don't know there are pastes made by just about every major paint manufacturer for scuffing up prepainted panels,mainly for doing blend work on cars but their use can also crossover into spotting in bikes.These pastes are usually used on a wet scuffpad and are excelent for helping abrade the panel and help immensely cleaning ground in grime off.Cleaning this stuff off is imperative and sometimes hard to see.The best way is to do a small area and rinse well and work your way from top to bottom,being carefull not to get alot of the paste around the nooks and cranies of moldings or any place water will drip out of later.When your done grab a fresh scuffy and the hose and rinse again.Have you ever noticed the dried water streaks running down a panel after it's been wetsanded and dries?These will show if there's any paste left in the drips.Prep solvent won't take it out either and looks like hell after it's cleared.Some pastes are colored too so all of a sudden there's a tinge of color under the clear-not good.Some things come off with water only,some with solvent only.To avoid catastrophies,wash the part in soap and water and then solvent wash.After any wetsanding or scuffing rewash with plenty of plain water.Before I tape I solvent wash again (mainly because service and detail love to spray things that paint doesn't like),and another one right before I spray.Another old trick before tacking is to wipe the surface down with water damp lint free towels until the towels show completely clean,you'd be surprised at the amount of dust still trapped in the sand scratches after you think it's clean.