Some of the washers are copper based they are only a few cents each if you really need to anneal (soften) copper washers hold in flame for 30 seconds then quench in cold water (copper being the only metal you quench in water to soften).
I use pensoil 20-50 diesel oil it is by far the best oil I have used. I tried Mobil 1 far too thin for our gear box so threw it out
give the diesel a try it is fantastic
