Large smokey fires will lower visibility and create updrafts to disperse tear gas.
They're helpless if they can see. Also, bottles of used motor oil thrown against the windshield and windows will block vision and provide additional fuel for firebombs.
The way you kill a tank is a gas bomb into the radiator. Once the radiator starts dumping heat into the engine instead of taking it away from the engine the vehicle get immobile real fast. Also it becomes an oven for the crew who have to bail out.