1. Soak the rainfly in cool water with unscented laundry detergent to break down the coating. Scents can attract skunks, bears, and other animals which is why unscented detergent is preferred (you may add a ¼ cup of ammonia in addition to the detergent to speed up the process). 
  2. For any tougher remaining spots, you can soak it in rubbing alcohol. It usually dissolves the urethane into a greenish blob. 
  3. After a thorough rinse, the fabric should be totally stripped of any coating. 
  4. Allow rainfly to air dry completely.
  5. Take a bristle brush and gently scrub the fly to remove any remaining urethane flakes that may be present. Stubborn spots may require additional rubbing alcohol.
  6. How do I apply waterproofing to my tent?
  7. After removing the delaminated waterproofing, We recommend products like GearAid Seam Seal TF (Tent Fabric) for the underside of the fly, and Revivex for the outside of the fly for additional protection. You may also use Tent Sure for the floor, and Gear Aid’s Seam Grip for the seams. Set the rainfly on the ground with the underside facing up (or out). Follow the instructions on the waterproof product to apply a new coating to the fly. This is also a good time to retreat the seams.