I cleaned, polished several classic vintage wrenches. Proto, Bonney, Williams, Herbrand and so on but only for a couple hours because unfortunately I had real chores to do.
I have had a couple ventless natgas and propane heaters over the years and every one of them, I thought, made me feel like I needed a vent. I never wanted to fall asleep in the room with one. But I'm more of a wood stove guy anyway so I'm sure my opinion is probably a little biased.