I think that getting the methanol out of the engine is most important. It is extremely hygroscopic, meaning that it draws humidity out of the air and that water stays behind when the methanol evaporates. Rusting was seldom a problem back in the days when control line flying dominated. These planes had no throttle and flew until the tank went dry. This ensured that the methanol in the crankcase was consumed. Also, with open exhausts, the engine was very open allowing any remaining fuel to to dry up.

Full scale race cars that burn methanol as a fuel are often run on gasoline for a minute or two to clear all traces of methanol out of the engine before being put away.