That said, this trick is only a precaution. It should not be treated as a fix for a sink that already has strong odors, slow drainage, gurgling sounds, or signs of a larger plumbing issue. In those cases, the better move is to look for the underlying cause or contact a qualified plumber.

If a home will be empty for an extended period, it may also be worth thinking beyond the sink. Depending on the property and local conditions, homeowners often check appliance settings, water-related risks, trash, food waste, thermostat settings, and general security before leaving.

What To Do When You Get Home

When you return, remove the glass and paper towel, then run water through the sink for a short time. This helps refill the trap and restore the water barrier that normally helps keep odors from entering the room.

If the smell disappears after the sink has been used, the issue may have been temporary. If the odor continues, possible causes include buildup in the drain, a dry trap, or a drainage problem that needs attention.

The upside-down glass trick is not a guaranteed solution, but it is a simple, low-effort step that may help keep your home fresher while you are away. Add it to your pre-trip routine, then keep an eye out for any plumbing signs that deserve a closer look.