Atomic force microscopy studies have been performed on substrates cleaned in a chemical beam epitaxy reactor using tris(dimethylamino)arsenic (TDMAAs) or tris(dimethylamino)antimony (TDMASb) at substrate temperatures well below those required for thermal desorption of the native oxide. For the first time, we report surface oxide removal from InAs(001) at 370°C using TDMAAs, and from InSb(001) and GaSb(001) at 405°C and 495°C respectively, using TDMASb. Atomically flat surfaces are achieved which are suitable for epitaxial growth without a buffer layer. Preliminary experiments indicate InSb growth may be achieved using uncracked TDMASb with trimethylindium. Decomposition studies of TDMAAs on GaAs using modulated beam mass spectrometry show an important change in the decomposition efficiency of TDMAAs above 480°C.