I don't have a lot of sympathy for squirrels in general. They may be cute, but they are pests. I am not a hunter -- I simply don't care for guns. You want 'em? Fine. I just don't have it in me.
Which is apparently why my teacher just called me. "Peter! Skunks! Under my house! Smells terrible! Help!"
Cayenne pepper. It's an old reliable for pest control. Works on insects, too. The capsaicin is a massive deterrent. Sprinkle cayenne pepper around where you don't want the skunks or across the entrance they use to get under the house, and you're golden. Sticking a bunch of mothballs in a sock and leaving it there works, too, or oil of mustard in a pinch. Doesn't kill them, just makes them stay away. Same with squirrels. Dirt cheap, no killing, no chemicals, totally granola. Just make sure you check it every few days to make sure it's still effective.
Teach is promising to take me to Portillo's the next time we meet.
Oh, and if you've got raccoons and want something non-lethal, just put a length of chicken wire across the ground. Raccoons walk on their front paws, and those are very sensitive. Walking on chicken wire annoys them, and they'll move on.