Zip-top bags are great, but sometimes you buy something in bulk and you're stuck with an unsealable bag. 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. Push the bag through the bottle neck, fold it over the edges, and twist the cap back on. Now your bag has an airtight and watertight seal, and you didn't have to waste the bag.
A Useful Re-Use of Plastic Bottle Caps [Re-Nest]