IF you want to, run some diesel purge through it... not through the tank, but from the supply lines (put that return line in the bottle too
)
My 7 year old diesel was OK to run on, little rough, but it worked OK as far as I can tell. Theres someone out there who found some 40? year old diesel in an apparetment or something for heating... Long story short a car ran fine on it, and so did the equipment that the guy who he sold it to uses...
~Nate