Subtracting sensors output that have mutual inductnace between them
This sounds like blind source separation.  In general, you can't unmix things after they've been mixed. If you have two different recordings of two sources with some of each source in each recording, you can sometimes use independent component analysis to separate them.

I have a Python example here.  There's also FastICA for MATLAB.  If they are audio signals, being picked up magnetically, there's probably no appreciable delay between them.  ICA works well in this case.