How to Suppress Peaks:
To suppress the solvent peak at the transmitter frequency:
Start from time domain. If you have already transformed the spectrum, choose File > Reload.
Choose Process > Suppress.
iNMR automatically inserts the transmitter frequency. Just click Suppress.
To suppress a generic peak:
Start from frequency domain. If you haven't transformed the spectrum yet, choose File > Fourier Transform, etc...
Right-click the unwanted peak and choose Suppress from the menu that pops up.
You can suppress up to 4 different peaks in the same way. If you specify a fifth frequency, the fourth peak reappears.
This simplified method deletes the frequency corresponding to the peak maximum. To delete a generic frequency, you have to type it, inside the dialog Process > Suppress, before performing the FT.
To make the suppression milder or stronger:
Choose File > Reload and Process > Suppress.
In the first instance, you should select the highest selectivity factor. It allows an effective suppression of the unwanted peaks, while preserving the rest of the spectrum almost intact.
When the unwanted peak is broad, decrease the selectivity factor. You'll get a stronger suppression.
To undo:
Choose File > Reload and Process > Suppress.
Empty the four cells.
Click Suppress.