After the PT well cleaned samples, which do not outgas at room temperature,show a different behavior at increased temperature. Already at 40 C these samples start to outgas strongly. This effect continues with a further increase of the temperature. Nevertheless, after 3-4 h of bake-out at 150 C the pollutions have disappeared, even at samples with normally unacceptable PT indications like at the sample nos. 7 and 8. Even so the temperature of the samples did not reach 150 c applied to the chamber wall, the cleaning process was sufficient. Fig.6 shows the mass spectra of the sample no.7 at a temperature of the vacuum chamber of 150 c immediately after the achievement of this temperature and after 4 h baking-out at 150 c