Fry oil to biodiesel...Why?

[mneary]

I think burning fry oil will make black smoke and stink as bad or worse as a diesel that burns petrolium diesel fuel.

Why do you think that? Ever seen one? I've seen a diesel which burns fry oil. It didn't put out any black smoke, and smelled nicer to me than diesel fuel. One nice thing about fry oil is that it is naturally low sulfur.

I think more crap comes out of a diesel's stinking smoking exhaust than goes in.

No argument there. I owned a diesel, and the exhaust was bad when it was cold. But then again I certainly wouldn't want to breathe (or drink) the raw fuel either.