How to make a simple water bottle filter.
Step 1: Cut a Water Bottle in Half.
You'll need either a knife or scissors. Cut the bottle in half.
Step 2: Place the Halves Together.
Keep the bottom part upright. Take the other half (the half of the bottle where the cap goes) and cover the top with a coffee filter and then place it inside the other half. Tie it in place with a rubber band. Make sure to press down somewhat to secure the halves.