Zip-top bags are great, but sometimes you buy something in bulk and you're stuck with an un-sealable 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 air and water tight seal, and you didn't have to waste the bag.
Cut up a disposable water bottle and keep the neck and top, as in photo.