Special surface cleaners are substances designed to clean certain surface materials such as glass, vinyl, carpets, and upholstery, to name a few. Glass cleaners typically contain water, glycol ethers, ammonia, and alcohols. They are commercially available as moistened towelettes or liquid or aerosol sprays. Carpet and upholstery cleaners are sold as liquid shampoos or as powders. Both forms may contain surfactants, foam stabilizers, alcohols, and/or glycol ethers, but the powders may have additional porous carrier materials that trap dirt.