I hate cockroaches. And I used to be scared of them. When I saw one crawling around, I could never bring myself to smash it with a shoe or even a rolled up newspaper. Ugh. The mess, the gore, the guts, the possible spill out of cockroach eggs from the dead cockroach, and the contamination of your shoe and house with roach guts. Plus the risk of one going into attack mode, flying at you, and landing on your hair or down your back. Did I mention I hate cockroaches? So my options were:

a) call someone to kill it for me <– downside: requires a person with the same sense of urgency and desire to kill a cockroach right at that moment or else the cockroach will have too much time to escape and hide

b) spray a ton of Raid on it <– downside: toxic smell, even if it’s the water-based Raid that smells better than regular Raid

c) light a candle or lighter and spray Raid at the flame to create a blowtorch and burn the cockroach to death <– downside: scorch marks on wall; also then-boyfriend (now Husband) might suspect you of being a pyromaniac

And then I discovered the best and cleanest cockroach killer– BUBBLES! Bubbles kill cockroaches almost instantly. It doesn’t matter what you make the bubbles from. You can use any kind of shampoo, liquid soap, detergent, dish washing liquid or soap as long as it makes bubbles. This is a good way to use up leftover shampoo or liquid soap that you don’t want to use on yourself.

Killing cockroaches with bubbles is easy, quick, and very satisfying. When you see a cockroach crawling, all you have to do is grab a container of water and squirt some shampoo or liquid soap into the water. Then you mix it up to make it bubbly and fling the bubbly water at the cockroach. Cockroaches breathe through openings on their bodies. The bubbles will coat the openings and suffocate the cockroach! Depending on your accuracy and the speed of the cockroach, you may not get enough bubbles on the cockroach on your first attempt. As long as you get some water on it though, this will be enough to slow it down so you can pour more bubbles on it until it dies. This is an effective method for killing cockroaches that are on walls, high places, and other spots that are beyond arm’s reach. It is easy to fling water at great distances with some accuracy and they fall off the walls as soon as you hit them with some soapy water. You can also use a spray bottle filled with water and shampoo or soap. This method uses less water, so it’s more economical and less messy. It’s best to use lots of soapy water though to ensure that the cockroach is really dead and not just knocked out.

Soaps in general are lethal to insects, because they are surfactants that make it easier for water to wet surfaces. Insects breathe through spiracles, which are openings (usually along their sides) that lead to a network of air channels that carry oxygen throughout their bodies. Normally water is prevented from easily entering these spiracles by its surface tension. Since soap reduces the surface tension, it makes it possible for the water to flow into the spiracles, and so the insect can no longer get oxygen into its body and rapidly drowns.

Source : https://www.quora.com/Why-is-shampoo-Dove-Head-Shoulders-lethal-to-cockroaches

Source : https://sylviatramos.blog/2013/08/18/the-best-and-cleanest-way-to-kill-a-cockroach