Home-centric blog Re-Nest shows us an easy way to give these bags an airtight seal with an old water bottle. All you need to do is cut off the top of the bottle and take off the cap.

The newly renamed Poly-Seal Corp. focused on one necessary but often ignored item: bottle caps. After all, every bottle needs a cap. But the caps aren’t made with the bottles.

Association of Plastic Recyclers: “Recycling plastic bottles: Here’s why you’re supposed to leave the cap on” Napa Recycling and Waste Service : “Beer Bottle Caps” lovelyday12/Getty Images ...

Next time you need to seal a bag to keep food fresh or stop it from spilling, use a bottle cap. Taylor Martin CNET Contributor Taylor Martin has covered technology online for over six years.