When I moved into my apartment 20 years ago, I inherited a bathroom vent without a fan. Unbeknownst to me at the time, city housing laws require working fans in bathroom vents (when the light is turned on). Well, mine was never fixed, and we taped a piece of aluminum foil around it to block any unwanted visitors from crawling through.
With much trepidation, I just removed that aluminum foil, as I saw what appears to be soot or mold creeping out of it. The vent holes are loaded with thick dirt (and possibly molds). What's the best way to clean it? Get a powerful hand held vacuum and a filtered mask? Any ideas?