@wildpotato Even though, when we listen to a recording, we can easily tell the voice of the professor from the clicking of the keys, it is very difficult to remove a specific sound from the recording and leave the rest. This is because, to the the computer or software, the sound is just one big wash of sound, no individual parts.
So, we have to find a way to remove the part we don’t want even thought it cannot be easily identified.
I said “theoretically” in my answer, because, theoretically, you can invert the waveform of the sound of a a key and add it in on top of the original waveform and cancel the sound of the key. But practically speaking, this is way too difficult to do, one key tap at a time, even if you could invert the waves, etc.
The best you can do with normal equipment, is find the frequency of the sound of the key and remove that frequency. It is really a range of frequencies, and the more frequencies you remove, the weirder the remainder sounds, kind of like being underwater, if taken to the extreme.
You can use a program like Soundforge to create a notch filter, a filter that removes a narrow frequency of sound, and play with removing different frequencies to see how well you can dampen the key sounds. Its not easy, but you might be able to reduce them by half with some work.
Good luck.