Need help cleaning noise
I took a look at your noise spectrum and it's pretty bad 

You have strong lines at 20kHz and harmonics thereof. But also some spurs around  15 kHz, 18 kHz, 25 kHz and 44 kHz. The stuff at 20 you could potentially reduce with a comb filter, but your best bet (by far) is to clean up your measurement/recording setup.

There is no reason for this noise to be there, and you should try to identify the culprit(s) and eliminate them. Look at interconnects, other devices in the room especially lights or communication equipment, electric interference, power supplies, grounding issues etc. 

This will be very hard to clean up, so having a good recording in the first place would be much preferable.