Before leaving for vacation, many people are trying a viral social media hack that suggests placing a sheet of paper over the sink drain and weighing it down with an upside-down glass. The idea is that this simple barrier will keep bad odors and insects from entering the home while no one is there. Although the trick sounds convincing, professional plumbers say it is not a reliable solution.

The reason lies beneath the sink in the **P-trap**, the U-shaped pipe found under sinks, showers, and bathtubs. This pipe always holds a small amount of water that acts as a natural seal, preventing sewer gases, unpleasant smells, and pests from traveling back into the house. During long vacations, however, the water can slowly evaporate, especially in hot or dry conditions, weakening that protective barrier.

Experts explain that the paper-and-glass method does little to solve the problem. A drinking glass cannot form a completely airtight seal against the sink, leaving tiny gaps where odors and insects can still pass through. In addition, paper absorbs moisture, becomes soft, and eventually loses its ability to cover the drain effectively. Instead of protecting the drain, it may simply become damp and ineffective after several days.

Plumbers recommend a few simple steps that work much better. Before leaving, run water in every sink, shower, bathtub, and floor drain to refill each P-trap. Then use the sink’s built-in stopper or a properly fitted rubber or silicone drain cover for a tighter seal. If you’ll be away for a month or longer, pour a tablespoon of mineral oil into each drain. The oil floats on the water inside the P-trap, slowing evaporation and helping the water seal last much longer.

Rather than relying on viral internet hacks, taking a few minutes to prepare your plumbing properly can help ensure you return to a fresh, odor-free home.