Many forumers here use waste oil. I don't use it because I don't want to let the neighborhood in the stench, despite I can obtain it for free at the local garage. Propane works well for me. But I think that this oil contains heavy metals, sometimes even toxic from lubrication and wear of engine parts. Or do you guys get other less polluting sources of waste oil ?
All the parts stores in my little town are not accepting waste oil.. I went shopping for parts, and they all three had signs up saying sorry they were full... Most likely the oil they can't take will be dumped.. Cooking oil is the only oil not likely to be contaminated with heavy metal. The biggest complaint there is the smell, and less btu..
I agree thats what I've always been concerned about. But who knows if its really a problem. Clearly people have used it for many years, decades even, and don't have heavy metal poisoning from it. So in reality its probably ok? But on paper I'm with you and there may be a risk. Just not sure how you'd gauge how likely that risk is. But free veggy oil is clean and ok to use.
I think one issue with used/waste motor/engine oils are the surfactants. Some having organometallics added that can't be filtered out. Any N/S compounds end up as NO2 or SO2 while Zn compounds will end up as ZnO.
