I've got a bunch of leftover grease from a veggie diesel van I sold and I need to know how to dispose of it. Some of it appears to be unused filtered vegetable oil and I'm assuming I can just dump this out, but some it seems to have engine oil or perhaps a diesel mixture in it. Can I dump this, too? Also, do you guys know if I really can run a Benz w123 on straight veg oil this summer? Thanks!