Below you can read about an effective remedy which will help you get rid of them and prevent their recurrence. The ingredients that this method contains are not deadly at all.
The ingredients you need to have:
5 oz. of 100% boric acid
You need to:
Boil the eggs for 15 minutes. First remove their shell then remove the yolks as well. Place them in a container and mix them with boric acid. After that you should add a cup of sugar in order to add to the consistency and continue adding until it stops being crummy, and becomes similar to play-dough.
The next step is to form it into balls and place them at different locations around the house including closets and shelves. Leave them like that for some time. You will start to see the dead cockroaches all around your house.