grease powered diesel Audi's?

[Steve Sherman]

Just to add my thoughts on this thread....

I am pretty sure that the dye is put into home heating oil.  That way if
you've put any in then when they stick a "rag" into your tank it comes
up colored.  The diesel fuel i put into my old truck is not colored...
Not that anyone here would try an cheat, but if you do, you don't want
to be adding dye.

The best way to use old veg oil for a diesel is to convert it.  There is
a book and a website out there that talks about it.  Basically you
filter the old oil, add the right amount of methyl alcohol and lye, heat
and mix, and voila you end up with a high quality diesel and residue
(glycerin or the like).  Sounds a bit messy, but if one is serious this
is probably the way to do it.  BTW - the same issues exist on taxes, you
are of course supposed to pay your road tax...