Adjust your pipe wrench so that it fits over the rag and is snug against the bathtub spout.

Check the underside of the spout next to the wall and look for a hole or screw hidden under the spout.

Once found, loosen the screw with an Allen wrench (but do not remove) the set screw.

Gently turn the wrench counterclockwise (to the left) until it is loose enough to twist with your hands.