1. Measure the size of the items going inside the case and cut the bottoms of two bottles off to half of that measurement. When you put the two cut bottoms together it should be large enough to hold the markers, crayons or pencils.
2. Wrap the zipper around the cut edge of the bottle to measure the appropriate length. Cut to length.
3. Cut a small rectangle of felt and glue it onto the cut end of the zipper to seal and cover it.
4. Zip the zipper up and lay it down. Apply Fabri-tac or glue using a low-temp hot glue gun to glue half of the zipper to the cut edges of the bottles with a little space in between so that the teeth of the zipper are free to open and close.
5. Continue gluing until the zipper is attached all the way around the bottle bottoms.
6. Put your supplies in and enjoy!