When I'm finished flying for the day I open the throttle wide open, connect my fuel pump to the muffler line, put my thumb over the carb openning and crank my six shooter to draw fuel out, then release my thumb. The very small amount of fuel actually left in the crank case holds the lube to keep everything from rusting and all of the liquid fuel from the carb back is sucked into the tank. Then I pull of my fuel line from the carb and six shooter the leftovers back into my can. Its just as clean coming out as it was going in to the naked eye and I go though a can of fuel about every three weeks or so and haven't had a problem with contamination or anything. My EVO starts on the first flip by hand after priming every time.