Yellow condensation stains often come from when there has been a leak in the roof of your home, or if it’s somewhere in your bathroom, it could be due to a lack of appropriate ventilation. The water then dries and causes the yellow staining.
Yellow stains on your ceiling can look unsightly but they can be removed. However, it is best to find what it is that has leaked, whether that’s a pipe that needs some plumbing attention, and fix it, rather than just covering up the staining.