first up use megs quick clay to get rid of all the bonded contaminants, then use scratch x to try to get rid of the blemishes, then use dc step 1 and and step 2 , then use the nxt tech wax 2 to finish it off.
this is the general recommendation on the megs forum
if you use them products in that order you will get a really good finish, after the clay you will be amazed how smooth your paint is.