Pre-soaking exterior contaminants with an all purpose cleaner like R222 Total Auto Wash will help to soften and remove them when pressure washing, and a gentle hand wash with normal shampoo should finish the job off. To remove more firmly bonded contaminants, please see these links for details on how to go about removing them and leave the paint feeling perfectly smooth...

http://www.polishedbliss.co.uk/acata...e-faq.html#2.1

http://www.polishedbliss.co.uk/acata...e-faq.html#2.2

http://www.polishedbliss.co.uk/acata...des_clean.html

Moving on to the polishing requirement, assuming you are working by hand, please see this link for details on polishing hard German paints by hand...

http://www.polishedbliss.co.uk/acata...e-faq.html#3.7

For details about what wax or sealant to use (and reasons why, plus example images), please see Section 4 of our FAQ, starting here...

http://www.polishedbliss.co.uk/acata...e-faq.html#4.1