An approach to suppressing spurious resonances due to the probe in NMR is presented which utilizes DEPTH (I) pulse sequences to select homogeneous regions of the radiofrequency field. This method is well suited to eliminating background resonances from the probe in Bloch decay spectra in solids and the glass resonance in solution 29Si NMR. Bloch decay spectra obtained in probes that are designed primarily for cross-polarization magic-angle sample spinning, CP/MAS, studies often contain resonances from materials which are close to the coil. These materials are needed for, among other reasons, insulating the coil and holding it in place, as stators and bearings in the MAS assembly, as insulation in quarter wave stubs, and for thermal insulation where variable temperature capabilities are desired. The actual materials, Teflon, Kel-F, boron nitride, Macor, and aluminum oxide, are generally chosen since they contain no protons and, therefore, do not yield a cross-polarization spectrum. In Bloch decay spectra, however, these materials do display broad background signals which makes the observation of dilute samples (e.g., surface species) difficult. Since these extraneous signals originate from well outside the coil, they are in a region of inhomogeneous and lower RF field than the sample of interest; therefore pulse sequences which are currently used in surface coil studies to selectively excite regions of homogeneous RF fields may be employed to suppress these signals. A similar case exists for 29Si NMR of liquids in which the glass resonance from Dewars, the sample tube and the insert on which the coil is wound, interferes. Figure I shows for various pulse widths the Bloch decay spectra of methylamine adsorbed onto a high-surface-area eta-alumina. The eta-alumina is a Bayerite with a surface area of 400 m*/g, donated by Alcoa. It was treated in vucuo for 2 h at 400°C with subsequent adsorption of methylamine at room temperature in a traditional gas manifold. The spectra were acquired on a Bruker MSL-400 with their broadband, variable temperature CP/MAS probe. The broad signal is from Teflon which is used to guide the spinner into the stator, as a thermal insulator which encloses the MAS spinning assembly, and as a dielectric in the transmission lines. It would be difficult to replace all of the Teflon in the probe without adding signals in the silicon, aluminum, or boron spectra for which the probe is also used. The sharp resonance at 24 ppm is assigned to methylamine species bound to Lewis acid sites. It is seen in the figure that the 90” pulse for the methylamine species is 4 ps, and that for the Teflon