The invention relates to a method for cleaning the process gas in soldering installations and solder suction systems, in particular for reducing the abietic acid in the process gas, wherein the process gas to be cleaned is conducted through a cleaning system which contains one or more of the following compounds (cleaning compounds): a) carboxylic acids with reducing properties, namely oxalic acid, formic acid, citric acid and/or ascorbic acid: b) metal compounds of higher oxidation states, namely manganates, permanganates, chromates and/or dichromates; c) alcohols which can be convened into the carboxylic acids mentioned in a) by means of oxidation; d) basic lime compounds.