I wont give any specific ideas so my door doesnt get a knock (they wouldnt work anyways, im a tard) but I would just move to a city I really really hate, spend thousands in buying like 100 kilos of medicines\pills\rat poison and bug spray, and somehow flush it all down, gradually but continually and steadily, trough the toilet. As well as flushing down 1000s of poisoned coins in hope of attracting the greed of sewage workers.
I would thus exterminate the city.