The invention relates to a process for treating a composition containing silicon compounds, especially organosilanes and/or inorganic silanes, and at least one extraneous metal and/or a compound containing extraneous metal, wherein the composition is contacted with at least one adsorbent and/or a first filter and then a composition in which the content of the extraneous metal and/or of the compound containing extraneous metal has been reduced is obtained. The invention further relates to the use of organic resins, activated carbon, silicates and/or zeolites and/or else of at least one filter with small pore sizes to reduce the level of the compounds mentioned.