Since we fly off a dirt runway I would never take an engine to the field without an air cleaner. A crash off field can put a lot of junk into the carb barrel. It will hurt the engine by scratching the polished internal surfaces such as the crank throws and bearings as well as the cylinder. Common practice at our club is never turn an engine by hand after a crash. Take it home and clean it. Tower sells Bruline carb air filters in a couple of sizes. I never thought of the pantyhose approach but it sounds good to me.