A new cleanup procedure is described for chlorinated hydrocarbon residues in butterfat. The method is based on the dropwise addition of H2SO4 to a fat solution column and continuous removal of the lipids and acid. The cleanup of 0.25-2.0 g fat requires only 10-40 ml H2SO4 and 12-17 ml petroleum ether. There is no need for any further cleanup step, solvent evaporation or centrifugation. The method is easy to standardize and suitable for automation. At least 30 fat samples can be cleaned up manually by 1 analyst in 1 day. Recoveries were complete (> 90%) for polychlorinated biphenyl compounds and for 13 chlorinated pesticides of 16 examined. The method was tested on chlorinated hydrocarbon residues in commercial butter, and the results were compared with those obtained with the acetonitrile method. The versatility and limitations of the method were investigated by varying the H2SO4 strength, initial fat solution concentration and column dimensions.