It should take you just a couple of minutes to have both cushions removed. First remove the bottom. It is secured with two large phillips screws at the lower left and right front of the seat. Remove these and the cushion pops out by jerking upward at the front of the cushion.

To remove the back cushion, unscrew the two torx-head screws on the lower back side of the seat. This allows the bottom of the cushion to pull away from the seat frame and slide out.