Hi guys, My friend has a 2004 BMW and asked me to remove a stain that was left by a bird droping. He left it on the car for about a week before bothering to remove it! He then tryed removing the bird droping with a SCOTCH BRITE PAD. So far i clayed the car and used SSR2.5 but there is still a quarter size mark left by the bird droping. P.S. I used a pc with a LC yellow pad. Any help would be appreciated on what I should try next. thanks