I have a friend wanting to get rid of a few barrels he has around the house. They had castor oil in them. I don't know much about castor oil but I know it's not a petroleum product and comes from the castor bean. I know with most barrels/tanks etc... basically just burn and clean it and good to go, but I know there are some things that are advised against like using fuel oil tanks because of the permeation of the fuel oil into the metal. Just wanted to see if anyone has used a barrel that had castor oil and to make absolutely everything is safe. Not sure if there is any paint on the inside, will post pictures when I go to look at barrels, but I assume paint will need to go if it's there. The UDS build seems like the perfect thing to do on a tight budget and I've seen lots of great Ideas. Suggestions welcome! I promise to build something you haven't seen yet! Tips on improving efficiency would be great too...my brinkmann makes some great meals with the mods...but she's too hungry!