Abstract: A method of charging a pyrolytic gas-producing reactor with waste fuel wherein the waste fuel is forced into the reactor by a ram and wherein air is prevented from entering the reactor and pyrolysis gases are prevented from escaping from the reactor by means of an ablative seal which is positioned between the fuel and the ram and which is forced by the action of the ram on the fuel charge into the reactor whilst in sealing engagement with the internal walls of the reactor, the seal being made of a material which will resist the high temperature and chemical conditions in the reactor for at least as long a period as is required for the seal to perform its sealing function and which is thereafter thermally decomposed into products which are not detrimental to the pyrolytic process or to the pyrolytic gases produced by the reactor.