Just wondering, how much crud is left behind after the filtering process?
Not a lot actually, what I hear you have to do is use Methylated Spirits and Caustic soda, approx half a tea-spoon per 1 litre of grease + 1 cup of meths, then you shake it like hell, wait 24 hours for the Glycerin to separate siphon that off as its worthless then chug the rest into the fuel tank.
"Would I turn on the gas if my pal Mugsy were in there?" "You might, rabbit, you might!" -- Looney Tunes, Bugs and Thugs (1954, Friz Freleng)