I have read that nylon brushes will create static and possibly harm your components. I heard this after I dusted my gpu backplate off. I would be careful, I didn't notice any damage but I'm not planning on doing it again.
I did this a few weeks ago with evga precision X, I used 60 fps and it was tearing a lot. I only ran it for a few seconds because it was so bad, I didn't test any other limits. I think adaptive vsync works fine instead though.