Rinse any residual soda from the bottle and remove the label using a utility knife

Cut around the upper third of the soda bottle

Remove the bottle cap, flip the upper third of the soda bottle upside down, then insert it into the remaining two-thirds of the bottle.

Slowly push the upper part down into the lower part of the bottle. This will create a snug fit between the two parts.

Create several vertical cuts on the inner part where the mouth of the bottle is located. This will allow the upper third of the bottle to tightly fit into the lower part of the bottle.

Tightly wrap duct tape around the edges on top of the bottle. Make sure that the duct tape has some excess on the upper part of it.

Create vertical cuts on the excess tape on top.

Tape the excess pieces of tape that you’ve just cut onto the insides of the housefly bottle trap one by one.

Pour the brown sugar through the upside down mouth part of the housefly bottle trap.

Pour a cup of white vinegar and a cup of water through the upside down mouth part of the housefly bottle trap.

Shake the fly trap bottle to thoroughly mix.