Remove the seats. Turn the chair upside down and use a screw driver to separate the seat from the chair frame and chair back.
Take off the fabric. Use a staple remover or a flat head screw driver to pry off the staples or lift the tacks holding the upholstery to the seat. Remove the fabric and stuffing.
Cut the new stuffing. Measure the chair seat and cut the foam or cotton stuffing so that it is one quarter inch larger than the seat all the way around.
Stuff the seat. Put the stuffing on the top side of the seat. Cover the seat with the fabric and turn the seat over so that you are looking at the underside.
Upholster the seat. Pull on the fabric to keep it taunt and staple or tack it to the chair frame, folding the corners tightly as you go, as if you were wrapping a gift.
Attach the seat. Flip the seat over and place it on the chair frame with the fabric side up. Use a screw driver to fasten it to the chair frame and back. Be sure to line up the screw holes and turn the screws as tightly as possible.