So you’ve run over a rock. You pop off your board and check. A hunk of your base sticks up—the worst possible combination of hangnail and engorged boil. Terrific. But there’s no need to go to the shop. Take off your other ski, and put it base-to-base with the damaged one underneath. Tilt the top ski to a 30-degree angle. Plane the edge of the healthy ski against the hangnail. Scrape from front to back only, and scrape it until it’s smooth. Resume shredding.