Propane, white gas, Coleman fuel, Sterno, solid fuels, stoves containing fuel
This description includes all camping fuels such as white gas, Coleman fuel, naphtha, petroleum distillates, propane, butane, Sterno, etc.
No amount of flammable fuel can be carried, including even residual vapors.
Camping equipment that contains no residual fuel, vapors or other hazardous materials is allowed.
Some airlines will not carry used camping equipment that has had fuel in it regardless of how well it has been purged.