Silicone water repellents: These products are not true fabric protectors. You can make your own silicone water repellent product with one part silicone oil and 9 parts mineral spirits. Fabrics treated with a silicone water repellent develop good water repellency, that's true. But silicone water repellents retain a tackiness that attracts dirt. Silicone-treated fabrics soil much more rapidly than untreated fabrics, have zero resistance to oil based stains, bond in oil based stains and make fabrics much more difficult to clean when finally soiled (than untreated). Manufacturers of outdoor fabrics, fabric convertible topping, carpeting and upholstery and breathable outdoor wet weather garments such as Gore-Tex® recommend against silicone water repellent products. Unfortunately, most fabric and leather "water repellent/fabric protector" products available to consumers contain silicone. For full information on silicone water repellent products go back to this link and scroll down to the related text and chart.
303 Products, Inc.: High Tech Fabric Guard