[header] How to catch flies [title] Make a trap from a plastic bottle. [step] One of the most effective homemade fly traps is made using a simple plastic water bottle. [substeps] Unscrew and remove the cap, then use scissors to pierce the plastic and cut off the top quarter of the bottle. 
Fill the bottom part of the bottle with a quarter cup (60 ml) of sugar, a quarter cup (60 ml) of water, and a couple of drops of blue food colouring. The blue colour helps to attract flies, but most colours or no colours will attract flies as long as it isn't yellow.