Get a few lemons and let’s start!
Cut 3-4 lemons in half and keep them on your oven shelves overnight. Do not forget to leave the door open.
Next morning, close the oven door and turn it on, preferably to 100 degrees. Keep in mind that you should not bake the lemon halves, but let their pleasant scent refresh your home instead. Once you notice that the lemons have soften completely, throw them in the trash can.
You will enjoy the lemon scent for days. Although you find it pleasant, flies definitely do not like it.
Natural tricks always work better than any conventional method.