From shower humidity to internal leaks and ventilation problems, these stains have all kinds of causes. But after you’ve identified what made the mark on your wall in the first place ...

Before applying any dye or stain, make sure to cover the walls, frames, doors, and other parts of the place that’s not supposed to get stained. Also, after each staining, wait for it to dry ...

The cell wall of most bacteria has an overall net negative charge and thus can be stained directly with a single basic (positively charged) stain or dye. This type of stain allows us to observe the ...