Turn cleverness of rats against them. When a rat gets caught harmfully, it starts squeaking very loud. It's a "Danger!" signal to other rats. Very often rats leave the palce after the very first such "Danger!" signal.
I used "Alt" glue to achieve this effect and get rid of rats when I lived in India. I didn't find it on Amazon, unfortunately. I believe, the Catchmaster glue boards may serve the purpose as well.
This is a technology-based modification of the Vadim's idea. Catch a rat in a somewhat harmful way and record her "Danger!" cry. Play the recording laudly whenever and wherever you need to get rid of rats.