Unless you fancy the slow and laborious method of humanely catching them and taking them miles away to release them ( they prob soon get eaten anyway) i think the only way is whatever is quickest.
Best thing is to read as many reviews of traps as you can and pick the best. A house cat would be good but not neccersaily the most humane. But if they get into the house you dont want them peeing everywhere. Juat tell em to stay in the loft or under the floorboards and not chew the cables. They understand English you know.
I heard a noise once in the loft and just thought it was birds ( they nest under the eaves) but it was a squirrel and before long they built a nest and i ended up with a family of 5 up there. Cute and clever but not when they chew your cables. Cost a fortune for the pestman to get rid of them. He only used traps but i'm not sure i could confront an angry squirrel even less kill it. Good luck.