:thumbsdn: on the used oil. As mentioned its contaminated, if not with metal, definitly with corrosives.
The difference between a light oil like sewing mach oil, and an engine motor oil is substantial. Also some oils are hygroscopic. (this comes up on my machine tools forum often, its the ability of oil to absorb water. Water + rust...) These should be avoided, as the absorbed water will corrode the bearings. Gun oil would be better than 3 in one as its certainly not hygroscopic.
The viscocity should be matched close to manuf specs, as too thick an oil could add a load to the TT rotation. Even if this did not affect rotational speed, it could add load to the motor, conceivably wearing/burning it out sooner. I colug imagine some using a very light grease, (NOT axle grease, probably something like gun grease.)
While I also agree using a special packaged vial isn't smart, (all you are really buying is packageing and advertizing...) using the wrong grade oil isn't either.