Well, I am paying the price for only being able to move oil only forward today. Our oil sits in huge oil tanks in a remote shed, and is brought into the system via underground lines. needless to say, our pickup line at the storage tanks is a little primitive. You just stick the suction hose into the tank, and pull off a load. It's been quite a while since those tanks have been drained, and I messed up by sticking the hose into one of the tanks too deep. Before I knew it, I pulled up about 500 gallons of crap oil, wings and fries. I tried to make the most of it by trying to filter it, but the filter bag housing didn't like this stuff at all, so some of this pudding landed in my oil heater. I thought we'd be ok. Every batch we have ever processed is cooked with a babington set-up to at least 240F under 25 inches of vacuum. Every batch I have tested has been well below the 500 ppm level. This batch that was not the case. same temps and vacuum, but When I did a heat and weigh, it was .99%! Now I get to figure out how to get this batch back outside, because I'm sure there is a bunch of crud in the cooker vessel now.
I'm rambling here, but I guess the moral of the story is have a way to drain individual tanks if you have a multiple tank setup.
"You want fries with that?"