Re: Mysterious substance on bathroom walls
That nasty brown gook dripping down your walls would be you, partly. When you shower, the oils in your skin, bath products, etc become atomized and airborne. These airborne particles pick up dust that is in the air. The walls are cool, the moist air is warm, causing condensation of the moist air onto the walls, depositing all the dirt, oil, and other contents onto the walls with it.
Simply wiping the walls down periodically will keep the brown spots and streaks away. Installing a good bathroom vent fan on a timed switch will go even further to reduce these deposits on your walls.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!