this has worked in the past and you will see it used on buildings and some homes.
Get a foam owl decoy. they even come with moveable heads that the wind blows around. This will work for awhile. Also, go to an archery supply store and get some fresh red fox urine in a spray bottle. this works great, but it dilutes after rains and has to be reapplied.
I have found old film round containers and drilled a small hole in the bottom. then fill the container with cotton and spray a liberal amount of red fox urine and then hang this upside down by a string in the squirrel area. this way the rain will not dilute it.
a combination of owl decoys and fox urine should work for a while. But they do become educated.