What two of the gents before told you is dead on, if you don't want to learn how to replace engine bearings. Get in the habit of pumping the tank empty or nearly empty, then run the engine until it runs the system out of fuel, then put in a few drops of after-run and spin it some more. It may run on the after-run oil. That means the oil has displaced some of the alchohol laying in the crankcase. If the engine is very warm or even hot, this is better, since the methanol will evaporate out of the engine. Many folks will plug the muffler and the carb inlet after running the engine dry and applying after-run. This will keep ambient moisture away from your bearings and help prevent rust. A well maintained glow engine should last for many seasons of flying. One that is not maintained will get rusting bearings and fail to perform in less than one flying season.

Good luck with your engine.