We have an enclosed building that has been spray foamed years ago. By now it's very dark and dirty in the building and we found out we can brush it down with the broom. It works well and changes it back to original color but it just creates a lot of dust. How dangerous is this dust, or is there some better way to do it?
The dust by itself isn't dangerous since the foam's not breaking up but large quantities of regular dirt and dust are not good to breath under any circumstance. You would be better off getting a good shop vac and vacuuming the foam with the attachment brush. If you could get one with a long hose so the pump wouldn't be exhausting into the same room it would be better. You should also wear a mask to keep from inhaling the dust.