Any ideas how to get rid of old tree sap and bird dropping marks on my 97 528? I tried waxing it, it doesn't go away. Dealer shop says it is hard to get rid of, if at all. Also how to polish the chrome on the windows frame? I applied plastic/lens cleaner per dealer, but it is still dull. Seems there is a plastic film coating on the chrome. Thanks. Someone said the solution for the second problem was already posted, but I could not find it in the archives.