My DH talked with a friend of his that owns a Janome & industrial machine dealership. They use (Super Lube) synthetic grease on all the vintage bushed motors & metal gear sets and has used it for several years with no issues. He said the Super-Lube never hardens and has never liquified to contaminate motor commutator & brushes. I already use this stuff on gears and will use it in our motors from now on. I ordered a dozen 1/2oz tubes. I suppose it would also work fine on plastic gears since it is not petroleum based, but you will have to do your own research to verify usage on plastic gears.