As I noted in your other related thread, I go to a Chevron
oil products distributor to get my THF. They are hard to find,
even though Chevron's HQ is in this area. I used the Chevron
corp website to find 2 distis in my area, but now it does not
seem to work. You might try calling one of their corporate #s.
Both of the distis I have been to (San Ramon and Gilroy, CA)
were happy to sell 5-gallon bkts to me retail.