Dang Richard, I must have been dreaming about your problem last night. Woke up with images of veggie snot dancing in my head
Somewhere during REM it came to me that you have that electric heater inline as well. I wonder if the element is causing some of the crud you are seeing? Maybe try running without that for a while. Coolant heat should be plenty.
Also keep a sample of the stuff. Experiment with it. See what it's melting point is. Sputter test it for water.
I've heard Methanol is a great cleaner of veggie crud, but it's also great for causing nerve damage and blindness. Use full precautions and in a ventilated area if trying that.
Got any pics?
I dosed my tank with KILLEM yesterday. Perhaps there was bacteria in my WVO? 
I fear a big buildup of the slime will cover the heater wire in the bottom of the bowl. Methanol, huh? I was hoping the solvency of B-100 would dissolve it but nope. So I will probably will have to clean it by hand and continually drain the bowl with the yellow lever until I'm satisfied. I still have 75 gal of the questionable oil. Once I've run that I'll clean the bowl. Don, I don't want you having WVO slime nightmares...go dream about solenoids. 
