Update on tests using Castor oil-
I've used Benol, still readily available, in both the Vaughn and Microcosm M90, for around 3 refills. I mixed 4 oz to 1 gallon white gas(camp fuel). For comparison, I have run Zippo fuel with a bit of Marvel in the M90 and Camp fuel with wd40 in the Vaughn.
I can't see any difference in performance using either. Wear will need more run time to determine.
Oooh, but the Benol smells so good. I might go a bit heavier on the mix- just to be safe but it runs good now.