Gateway Waterproofing Powder .25 oz.. Pour the powder into a zip lock bag insert the fletched end of the arrow into the bag and shake it after that lightly rub the powered material into the feathers to waterproof them. Package Contents: Gateway Waterproofing Powder Waterproofing in powder form for use on arrows with feather fletching. Pour the powder into a zip lock bag insert the fletched end of the arrow into the bag and shake it after that lightly rub the powered material into the feathers to waterproof them.