Building debris
You should never dispose of building trash down the drain, regardless of where it comes from. This applies to trash in the form of powder as well as very microscopic bits. Large pieces can cause clogs, while tiny pieces can become stuck on the drain's sidewalls and cause even bigger issues.
Sanitary pads
Although they may initially appear to be entirely harmless, you should be aware that they are composed of latex, which never degrades. They have a strong ability to stretch and become lodged in pipes. In addition, condoms have the potential to fill with waste, water, or air, which can cause a significant clog that may be difficult to remove.