Several electrolysis experiments of loading deuterium into different metals foils and thin film films are described. Before and after loading the cathode surface was analyzed by Scanning Electron Microscopy and by Energy Dispersive Spectrometry. High magnification images of the surface of several metals were taken. A control experiment was conducted to make sure that the experimental setup is not accidentally contaminating the samples. A surprising amount of carbon was found on the cathode surface after each D loading experiment. The result is discussed in connection with other experimental results on low energy nuclear transmutations.