Not really extraction but this was part of an idea to solve the same problem. On a recent trip to the Derby Makers (more on that later) I was able to draw and print a quick and easy 3D part. The idea is that extending the nozzle should bring more of the air assist air down to the surface of the work and I would get cleaner cuts (the whole point of this exercise). I made the nozzle attachment intentionally long with the idea of cutting it down, I forgot that the red dot beam alignment would be blocked so with a quick after market modification it was ready for testing.
I think it did help with reducing the char marks on the work. I think that when my bigger air pump arrives that will probably help a lot more. The biggest downside is that the 3D printed plastic just holds the residue on the surface so when I accidentally bumped the work into it, it left a large brown smudge across the top which was far worse than any of the smoke staining so I'm going to rate this one as a moderate success with room for improvement.