Well, yeah. Assuming it were a more annoying frequency for you, what would you do? Probably won't be useful to me, but who knows.
I might do some of the following:
- Record the signal and use a denoiser after the fact
- Use a multiband noise gate to duck the volume whenever there's just noise going on
- Record the signal and manually automate the volume of a peak filter to achieve the same result as above but better
- Blend the signal in with a similar sounding synthesizer
- Play around with Vocodex and hope for the best
But mostly if the 1st option wasn't enough to get the result I wanted, I'd try to get a better signal before doing anything else, unless I had no other choice but to use that signal no matter what (or if I had to do it live).
A notch filter is a pretty heavy-handed approach but it works if there's nothing important going on at the frequencies in question.