If you absolutely must kill squirrels instead of poiosn use one of many lethal traps available in home and garden stores everywhere.
How to kill squirrels in your attic.
Trim any trees that overhang your house as squirrels and other pests can gain easy access to your roof windows and attic.
Take necessary precautions if you have children or pets as they can get caught in the traps as well.
You can find such a trap at many home centers like home depot.
If you want to get rid of your attic squirrels now for the least cost time and trouble these ultrasonic pest repellers are the only way to go.
A humane way to eliminate squirrels from your attic is to catch or trap and release them back into the wild.
Also if you do manage to kill one with poison the smell of a rotting squirrel is terrible.
And rat poison is not designed for squirrels so if they did eat it they may not die.
Reliable the only other solution to an attic squirrel infestation is to set up a series of fairly complex traps and wait for the squirrels to leave.
You can also set up bright lights in your attic since squirrels prefer to nest in places that are dark.
There are no registered rodenticides for squirrels.
The traps are made to be enticing effective and fast in trapping and killing a squirrel that may have made a home inside your property.
Trap and release squirrels in your attic.
The first step in this process is to obtain a no kill trap specifically designed to catch squirrels.
If the squirrel population around your home is a problem use traps to alleviate it.
However beware they are difficult to set.