Anyone been watching soccer lately? If so, you may have noticed a buzz in the background, created by many people playing the vuvuzela. This contribution on the File Exchange by Choqueuse Vincent might help you filter the sound track! Vincent uses the spectral subtraction method to achieve some nice results.
When I was studying Earth's magnetic field, we always joked that one person's noise was someone else's signal - because the main contributions to the magnetic field are crustal contributions, deep Earth contributions, and those external to the planet. I was at various times trying to model or understand contributions from Earth's interior (sometimes crustal, sometimes core) while others were studying the external sources. Because we could apply at least a simple model to the sources we weren't studying, we were each able to model the sources of interest.
Do you have the luxury of understanding enough about the sources of noise in your data? Let me know here.