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Summary form only given. The low pressure vacuum arc cleaning is a smart processing way of removing an oxide layer. The chemical and mechanical ways are mostly used to remove it, currently. However, both have severe problems such as liquid wastes, dust and noise. In the case of low pressure arc cleaning, there is only one place where the waste comes, from the oxide layer. In addition, because the cathode spot is very high in temperature, it has enough energy to remove the oxide layer. In this paper, removing an thin oxide layer on a thin metal plate was discussed. Scanning electron microscope(SEM) was used to observe the surface of the metal layer, and glow discharge spectrometry (GDS) and Auger spectroscopy was used to analyze O2 and Fe constitutions. In addition, high speed video camera was used to inspect the cathode spot movement on the metal surface. As a result, the low pressure arc can process thin oxide layers from a thin metal plate in a very short time (less than a second). However, some places on the plate after the treatment has a dip like a crater size about 50 mum in diameter at 20 A. The diameter of the crater gets smaller as the oxide layer gets thicker. And the constitution analysis shows that the amount of oxygen which was left over after the treatment didn't depend on the depth of the oxide layer before the treatment. So we can figure out that the dip does not depend on the leftover oxygen. From the numerical analysis, when the oxide layer gets thick, it needs more energy density to evaporate the layer. Therefore, smaller cathode spot would be needed. However, if the cathode spot is too small (too high in energy density), the spot does not only evaporate the oxide layer, but it will start to evaporate the metal surface. Therefore, that is one of the reasons why the crater gets larger when the oxide layer gets thinner.