Inexpensive and Easy Way to “Catch” Mosquitoes

We have many kinds of oils. But what is to be used to “catch” mosquitoes is found in the kitchen. It’s the used oil that is to be placed on a semi-flat plastic plate (the unbreakable type).

Spread the used oil exactly on the plate, and, with one hand, maneuver it where there are mosquitoes. You can catch mosquitoes even in one maneuver of the plate. The mosquitoes will be mixed with the oil and subsequently they die and they have to be removed at once from the plate so as to catch the other flying ones.
Mosquitoes often came out to the open when there is no light in the house.

So why buy expensive chemicals to kill mosquitoes, if there is a cheap oil to use?