I have an 06 ML500 and absolutely love it but some things just get me really angry. there is this spongelike material at the rear wheels that attracts dirt and leaves/grass. I tried spraying shredded leaves off but they are just sticking to the spongelike material at the rear wheels. Why did mercedes even bother to put such a material at the rear wheels? My 2006 ML500 is the only car i have seen this material on. Dirt and leaves stick to it and it sucks trying to take it off! Please HELP!