In many states, the poisoning of squirrels is illegal. Additionally, some areas have a protection act or require the use of a pest specialist to remove squirrels. It's important to check local laws pertaining to squirrels and investigate humane options for removal.
A popular option for trapping and relocating squirrels is a single animal live cage trap. This trap is used by both professionals and homeowners. The trap is a metal cage that leaves an area for food to be placed, in hopes of luring the squirrel in to eat. Once the animal has entered the area, it trips a plate, which closes it into the trap. It is suggested to not purchase a trap larger than 16 inches in length and 5 inches in height, as too large a trap can lead to an injured squirrel.
A similar option is a repeating live cage. This cage is used mostly by professionals but also offers homeowners an option for the humane removal of squirrels. The trap operates exactly as the single trap, except it leads the animal to think it is exiting the home through a one way door rather than trapping itself on the other end. This particular trap is large enough to capture several squirrels at a time.