[Richard]

Pure ATF will burn cleanly in a diesel engine. It is low viscosity and high detergent, so it has been used to clean injectors. ATF because you can carry it in a sealed and clean container. When you fill the filter, you can fill the "clean" side, so you  don't want to take a chance on putting contaminated fuel on the downstream side of the filter.

It is an old school truck driver trick.

Diesels were originally designed to burn about any mid weight hydrocarbon including kerosene, coal oil, and vegetable oil. Of course today, the electronic control systems aren't really designed to handle that range of fuels. Some of them aren't compatible with the engine or fuel system seals and hoses. There is a known issue with people using biofuel for the first time and it really messing up the system. The reason is that the biofuel is a solvent for some gunk that diesel is not. When you put it in an older system it dissolves the gunk and puts it right in the injectors. You could burn used motor oil in the diesel if you had a way of removing the additives and particulate. It's not really cost effective though.