Methods for killing rats in a home are using rat traps, using rat poison or shooting the rats. However, poison may not always be effective in actually killing the rats, and shooting is challenging and may cause damage to the home if done indoors.
The first step should be cleaning and sanitizing the area in which they have been sighted. This should include sealing all potential food sources. Set the traps in areas that the rats are likely to visit such as along walls, in the basement or in the attic. Make sure to check the traps regularly and change the bait.