The surface of a solid barium sample has been studied by surface analysis techniques. The procedure to obtain a clean surface is discussed. In depth distribution of the sputtered ions during cleaning provides a good way to understand the evolution in the surface composition. Ion images show clear differences in the composition of the sputtered spot relatively to the adjacent area. The acquisition of XPS and AES spectra showed that the surface is clean according to usual guidelines. However, positive and negative SIMS spectra gave insight in the identification of the low level contaminants. About 12 compounds have been identified on the 'clean' barium surface.