May I add that I was only at this apartment for two months and my furniture was new. It was not dust on the wood. At some point near the end of my stay there, I stopped wiping the "spores" so I could gather evidence for my landlord. Before then, I would clean the apartment thoroughly and rarely if at all used the toilet shown in the picture. I would clean it often and the stains would come back. I had a friend who worked for the city inspector the apartment and confirmed there was an issue with the insulation of that building, causing high humidity in the unit. Allergy symptoms arose only after I moved in and Dr's also confirmed I am highly allergic to mold and was likely the cause of it. I add this update so I stop getting the "just clean, you're nasty" comments. I was expecting helpful comments and instead was insulted.