Our writer tests several tactics and products promising to remove scratches from your vehicle’s paint, be they tiny or deep. The scratch was small, maybe half an inch long. Hard to even see unless you knew where to look. But once you knew, it was the only thing you could see. It was all I could see, anyway. I had only had the car for two weeks when the scratch appeared. I’d gassed up just once by the time I saw it, right there on the hood. How could it have happened? A mishap at the car wash? A passerby I’d wronged? Some kind of deranged animal? It wasn’t from another car or falling debris, that was for sure. But what could have left this blemish, marring my beautiful new Mazda CX-5 with less than 300 miles on the odometer, leaving behind a scratch so deep I could run my fingernail inside it? From the looks of it, it went all the way down to the primer. My quest to remove the scratch took me first to my local car wash and detailing center, who always seem to do good work. The guy with the clipboard said that for $100 they’d hand-wax it and try to buff it out. I crossed my fingers, but after the detailing the scratch was still there. I asked the tech...