Sea sponges are ideal for washing cars and trucks because they are extremely soft, especially Sea Wool sponges which are best suited for this purpose. Yellow sea sponges (Yellow refers to a type of sponge, not a color) are also well suited to washing a car or truck. They are almost as soft as the Sea Wool sponges, but a bit more durable. Although natural sponges are coarse and stiff when dry, they become extremely soft and absorbent when rewetted.
Natural sponges remove large amounts of grit and dirt from the finish and pull it into the pores in their surface, away from the paint where it could otherwise scratch the finish. When rinsed, natural sea sponges release the absorbed grit and dirt into the rinse water more completely, reducing the chance of un-rinsed grit building up in the sponge and scratching the finish.
Natural sea sponges are also extremely durable and can last for years with normal use. Never use harsh chemicals (bleach, ammonia, etc) when washing your car, because it will harm both the sponge and your vehicles finish. Always use a soap specially formulated for washing cars, any brand of car wash soap will do. Natural sea sponges also require less maintenance than some of the other types of popular sponges. After a quick thorough rinse to release any grit and dirt from the sponge, including normally hard-to-remove brake dust, a natural sponge will dry out and be ready for its next use.