Adding old oil to fuel?

[99nouns]

I have a couple of drums of unused but probably 15 years old rotella-type motor oil that I don't want to use as lube oil in my engines due to the age.

You can always use it in your chain saw, or sell em cheap on CL for people with chain saws...

 

[Stonewall]

I used to own a Deuce with the Hercules multifuel. it ran great on waste motor oil or anything else. Does anyone know why other diesel engines don't use that engine design? I know it was a compensator valve that would adjust to fuel viscosity.