roaches from coming out. leave the jar open overnight and you will find hundreds of dead roaches in it. the key in this trap is the coffee, which the roaches love. the roaches will die after 30 to 40 minutes of being submerged in the coffee-based water of the trap.
you can also use fly traps as roach traps. similar to the coffee jar trap, you can put grounded coffee or other stuff that roaches love in the middle of the fly trap. the roaches will be attracted to it and will try to fly over or crawl their way to the coffee. due to the sticky glue in the fly 