other squirrels cannot come in. you should try to scare them out before you plug the hole, but if they remain in the attic then you should go to step two. step two for getting rid of squirrels in the attic is to place a couple of traps in there so that you can get the little rodents out. the numbers of traps that you will use depends on two factors; the first is the number of squirrels that you have in the attic and the second one depends on how fast you want to get rid of the squirrels. because the hole is plugged you should not go cheap 