Studies into the effect of hydrogen and oxygen on the growth of CVD diamonds have been in progress for a number of years. Surface oxygen studies on natural diamond using Rutherford backscattering spectrometry have yielded partial monolayer coverage on low index planes. To increase the sensitivity of the measurements, elastic scattering using the 1 6 O(α,α) 1 6 O resonance at 3.045MeV has been performed. This resonance can enhance, by up to 30 times, the Rutherford cross-section. The samples are natural diamonds with either (111) or (100) surfaces. These have been cleaned using aqueous and acidic solvents to study the effect cleaning has on the oxygen coverage. We have found the coverage to be dependent on the vacuum level of the target chamber, with no effect being shown by the cleaning methods.