It's a good idea to use the after run oil after a days flying. It helps to chase away the nitro and methanol in the engine. This lengthens engine bearing life. At the end of the flying season, remove the glow plug and squirt some oil into the cylinder, and into the carb and spin the engine for a few revs. Get the oil everywhere in the engine you can, replace the plug, and store clean and dry until next season.

Another after run oil is Marvel Mystery oil. Works as well as the others.