Have you considered just adding a gallon or so of cheap veggie oil (fresh, not used) to the tank before refueling w/D2? The fuel terminals call that "splash blending". (A drive down a bumpy road immediately after fueling completes the blending.) I'd start with 1 gallon per 10-15+ gallons of D2 and see how it smells. Adjust according to 'scent'. Don't do this in colder climes - gelling/clouding issues.