Type "bc_mod qfil"
Type "bcfw 0.02"
Type "efp" to reprocess your data
This will null a region 0.02 ppm in width at the center of the spectrum. In the unlikely event that you have a real signal at the exact center of the spectrum, you should not use this technique as it will null out the real signal as well. Below is an example of removing such a spike in a 13C NMR spectrum.