I've found thus far that TC butterbore is useless below about 40 degrees F. It becomes to hard to squeeze out the tube. So I tried a solution of Murphys oil soap and Butterbore warmed together and soaked into patches that are in a old RB container. This worked pretty good, and the fouling was minimized. I don't have any castor-oil or I would try that. Maybe I'll pick some up this week and give your potion a try.