You could try to put together your own cones using parchment paper and a piece of tape, but these cones were $14. for 100, so ...

Release any flies who are in your trap, then make the paper cone with a smaller hole in the tip. You want the hole to be barely larger than a fruit fly.

To make these, you will need: bread, two baking sheets, parchment paper, and a cone roller (which you can either make out of a piece of still plastic or purchase for less than six bucks).

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