Nikwax Rug Proofâ ¢. Nikwax Rug Proofâ ¢ is an easy to use, safe and high performance wash in waterproofing for animal rugs and coats. Nikwax Rug Proofâ ¢ adds DWR (Durable Water Repellency) to coats and rugs, and also revitailises breathability and insulation. Nikwax Rug Proofâ ¢ is applied in the washing machine which ensures the DWR (Durable Water Repellency) treatment penetrates throughout the entire fabric of the garment including seams, tapes and cords. Nikwax Rug Proofâ ¢ is non-flammable, contains no harmful solvents and is free of harmful volatile organic compounds (VOCs) and fluorocarbons.