Flammable liquids, n.o.s. (not otherwise specified), listed in section 1211.150 for reference to this section, are restricted to a maximum quantity per vehicle^* of 100 gallons or 1000 pounds gross weight provided, however, such liquids are in inside glass, earthenware or polyethylene containers of one gallon capacity or less, or in metal drums or containers of 5 gallons or less, except that when the flash point is known to be above 20 degrees Fahrenheit, and is so indicated in the shipping document, the maximum quantity allowed per vehicle^* will be 200 gallons or 2000 pounds gross weight. There are no restrictions on the transport of empty containers which last contained such flammable liquid provided, the accompanying shipping papers show that they are drained of the liquid and securely closed.