Disclosed is a dense fluid spray cleaning apparatus comprising a gas supply (3) for providing a predetermined amount of a gas to an enhanced joule-thompson condensation reactor (2) and for providing gas to a propellant generator (4), a premix chamber (6) for receiving a solid particulate from the enhanced joule thompson condensation reactor and heated gas from the propellant generator, and a mixing chamber (8) for receiving the solid particulate and the heated gas and producing a spray stream containing the solid particulate.