My brother and father both have grease cars… They paid off the initial investment as well as cost of the vehicle in 2 years or less…
they are driving for free now.
father - i think an 198(mid) 300td merc
brother - 1995-1997 F 250
100% correct, some restaurants will actually drop off the oil to you in jugs, or there are kits that you can just suck it out of the bin in the back