70% IPA isopropyl rubbing alcohol will take sharpie off too.
I use a dryer fan/motor that I pulled out of an electric dryer a while back.
I mounted it to the wall and sent its 4" duct out, and ran a 6" duct from its inlet to my welding area, then use a reducer to 5" and a flex-duct to position the intake about 10" from where I am welding at the time. It doesn't seem to affect the shielding, and I cannot smell even a hint of ozone or other fume. I would weld galvanized without a respirator and when I get done and lift the hood, I can see all of the smoke/fumes going into the inlet. I am quite happy with it.
A dryer motor may be hard to acquire, but if you go to your local HVAC installer and ask for a HVAC blower, they might be able to help you out, and one of those would be enough to make a large fume hood. I went to one of the places local to me, asked if he had any. He did not, but offered to hold a few back for me. I asked for three. Two weeks later, he called and had two nice blowers setting there waiting for me. All free
I assume they pay to dispose of these things, so I am saving him money by taking off of his hands what he would otherwise have to pay to dispose of.