After a thorough inspection, I discovered that the squirrels were entering the attic area through the attic fan and the static vents.
So I installed an attic fan cover and attached a one-way device to it. By doing this, the squirrels will be forced to exit the area through the one-way device, which will allow the squirrels to safely leave the attic, but prevent them from getting back in.
We also placed several baited traps nearby.
To make sure the squirrels exit through our attic fan set-up, we installed a static vent cover which is made up of heavy duty, 18 gauge expanded galvanized steel which won't rust or corrode.
Once all the squirrels were safely removed, we relocated them to a new, humane location, cleaned up the attic area, and installed a new attic fan cover.
A homeowner in Pennington, NJ was having an issue with squirrels in his attic.