I contacted Pledge last week, and inquired them about their Pledge Multisurface Wipes. I love the product and use it heavily but I recently became concerned over what exactly is preventing them from developing mold. The product is usually always wet. They responded and said Quaternium-15. As a customer I feel pretty satisfied with that answer, I would much rather deal with a preservative than mold.. mold is definitely bad, especially against wood.