Small end-sealed samples of pine-sapwood (1.5 x 2.5 x 5 cm³) are treated by brushing and afterwards different parts of the treated surface are removed. The remaining part of the sample is tested against either insects or fungi. If no attack occurs sufficient amounts of biocides have been penetrated at least beyond the zone which has been removed. In spite of some problems the test seems the only suitable method, to evaluate organic solvent preservatives, mainly those containing resins, for simple treating methods.