Originally Posted by ArchaicArcane

I still stand by my theory that some of that old caked on oil isn't oil. I think it's the anti-corrosion film applied to the machine for transport. The first steps in the service manuals of old are to the effect of "Wipe all traces of the anti-corrosion film from the machine, paying special attention to the tensioner and hook area." I think many technicians wiped off traces in the visible areas and poorly at that, and that's what became the base for all of that stuff that sticks and hardens to cement especially in the "creases" of the machines.