Confirms my belief that squirrels are assholes. We have some that urinate on our deck. They also pick and take a single bite out of our tomatoes and lemons, spoiling an entire harvest just before we pick it.
(Not that I blame you for squinting them, I am only providing reason why, perhaps)
Get yourself a good, sharp paring knife or pocket knife and some kitchen shears and you're good to go.
Having said that, I tend to lean on the side of the other poster in that harming animals should be avoided unless there's a specific reason (such as eating them)
At some point the world isn't kumbaya and the animals will learn when they tend to die or be physically hurt when approaching that activity.
And you can sell squirrel caps to the neighbors' kids.
(inb4 beetlejuicing.)
It is often illegal.
I worked with them for about three hours, and at the end sent them home with a male rat. Both delighted as can be.
He was a very social and playful one that I had been planning on taking home.
I removed squirrel carcasses from all rooftop A/C units, along with the harvested nutshells that they had left behind. I patched the holes they opened into the walls and crevices of the condo apartments.
Finally I helped remove the 40-year-old pecan tree adjacent to one building's slab and which had hosted these pests for decades. The tree was lifting the slab and likely would have broken the foundation.
I have resolved that buildings should never coexist with either large trees (nut-bearing or otherwise) or with rodents.
Two years ago some jackass planted two pecan trees in the condo front yard. This year the pecans are falling and the squirrels have already moved back. The homeowners' association is clueless. The cycle continues.
Once, years ago, they went on a long vacation. The squirrels didn't like that the humans weren't setting out the buffet, so they broke into the food storage: a bog-standard rubbermaid style 55-galon outdoor trash can. They chewed right through the lid.
Solution: replace with a bog-standard metal outdoor trash can. After the next vacation, my parents came home to find tooth marks on the lid, signs of an attempted but thwarted break-in. Battle: Humans. War: On-going.