Mercury Quicksilver - High-Gloss Cowl Finishing Compound Surface Restoration Fine Grit 8M0168837. Overview. Any boater who's spent time around docks, trailers or tight marina corners knows how easy it is for a cowling to pick up small scuffs and scratches. They're minor, sure-but they tug at you every time the sun hits them just right. The Quicksilver 8M0168837 High-Gloss Cowl Finishing Compound brings back that clean, deep shine that makes your engine look cared for and ready for the next run.