Get an exterminator to get rid of them now and then get a trap and start relocating some in the summer.
I have this trap...works like magic...is a bit bigger than the one mentioned above. Squirrels are crafty and don't like to go in small spaces.
https://www.amazon.ca/Havahart-1083-...xpY2s9dHJ1ZQ==
You can use it for skunks too. Don't ask me how I know that

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EDIT: I forgot to mention that I used Cal-Rid to get rid of a skunk that I unintentionally trapped. It cost $350 for a skunk, not sure what squirrels in your attic would cost. However, if you don't get rid of their entrance, squirrels will always get back in.
https://www.cal-rid.com/