US Patent 8206488 Fluoride ion cleaning method

A fluoride ion cleaning method includes generating hydrogen fluoride (HF) gas in-situ in a cleaning retort; contacting a part in need of cleaning with the generated HF gas; scrubbing an initial effluent stream in-situ to substantially remove residual HF gas therefrom; and passing the scrubbed effluent gas stream out of the cleaning retort. In an exemplary method, a liquid or gaseous halogenated feedstock is introduced into a cleaning retort; hydrogen gas is introduced into the cleaning retort, HF gas is generated by a reaction of the feedstock with hydrogen gas at a sufficient temperature. In an exemplary method, only HF gas generated in-situ or reconstituted in-situ is utilized in the cleaning process.