Zinc oil supplement

I agree, unless we are talking extreme situations. found an old case of 10w40 in the corner of the garage ( probably there over 15 years ) . at the bottom of the bottles is a caramel colored sludge. might be able to get it resuspended if I put it in a paint shaker when it was warm.
I feel certain you could. Oil never goes bad. It just loses its additive effectiveness. I had a case of 5x20 I got for Kitty's Escape a while back that was "remanufactured" oil. There's a place in Macon that does it. Perfectly fine. The price was pretty close to what I can get it new, so I didn't bother again. They offer it really cheap in larger quantities.