I use a proccessor kit, from
Biodiesel Kits - Biodiesel Processors - Making Biodiesel , you pick up the WVO ,take it home, i pre-heat and pre-filter it in a 55 gal drum and a pair of levi jeans, so it pretty clean when it is put 40gal of WVO into the processor, then put a certain amount of lye , mix good, let settle, then drain off the dark gunk on the bottom, then you mix about 8 gal of methanol with it, then you run it thru a good filter into a Storage drum, you have about a total of 1hr hands on time and takes about 14 hrs for the total process, you'll have around .50 cents to .90 cents a gallon in it., you can run 100% or any mixture with regular diesel. over 12,000 miles and no problems..