Working on tender whistle, and getting ready to put back together. It is either a WS-85 or WS-75. Have not run it yet to find out. Part diagram says the brush plate (WS-66) has grease retainer WS-53. Instructions for lubrication say to use oil. Which is correct? I am contemplating inserting wick material in the grease retainer saturated with grease (high-temp automotive wheel bearing grease). I had to clean the commutator and brushes of all the black grease junk from all the surfaces and don't want the lubricant migrating to these areas again. Any suggestions?