Canisters are cleaned for reuse by evacuating and refilling with nitrogen or zero air multiple times to completely eliminate VOCs introduced during the previous sampling. After cleaning, canisters are left under vacuum in preparation for resampling. System pressure and vacuum readings control the evacuation and fill times for consistent batch to batch cleaning. Silonite® coated manifolds and separate fill and evacuation flow paths ensure the most rapid elimination of VOCs and SVOCs possible. The “D” models now include method control of oven temperatures and adaptive feedback and control of the molecular drag pump system to improve pump system performance and longevity.