We just bought a new silicone basting brush and are they fantastic......
How to use - Basting brushes come with bristles made from a variety of natural and synthetic materials. Unlike basting brushes with nylon bristles, silicone-bristled brushes can withstand temperatures from 500 to 800 degrees F, which makes them useful for applying marinades and sauces to items on the grill or hot broiler pan. Unlike natural porcine bristles and goose feathers, silicone bristles stand up to washing in the
dishwasher, which ensures adequate sterilization in the hot water cycle and is useful if you'll be using your brush to apply a raw egg wash.
Source -
How To Use a Silicon Basting Brush | eHow.com