Just dealt with this for a few weeks. I got some squirrel repellent balls that are coated in concentrated garlic and peppermint oil and threw them in the attic. They left after about a week. The smell took a bit to subside but wasn't too bad 💁♀️
If those are the noises you're hearing from your attic, it likely isn't a squirrel, but a ghost and either a snake or cat. Possibly a Ghost Cat or Ghost Snake? HTH!