By using old empty plastic water bottles, you will never need to buy small plastic funnels again!
You will need regular sized water bottles (empty)
a sharp knife
Step 1: Take a plastic water bottle
Take a regular small water bottle and cut the bottle about a third way down from the top and recycle the lower portion. You will be using the top part of the bottle only. You can recycle the cap.
I cut my bottle on a cutting board to avoid damaging the working surface.