When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
as above. something like poorboys apc or bug squash that can be sprayed on. leave it to soak and then use water under normal pressure. it may take a few goes but you'll get there.
just need to be caefull. you could use a very soft detail brush for the really stubborn bits. bit even then you're going to risk damaging the fins. may be an idea to follow up with a good degreaser to get any last dirt marks off. but to be honest the bug and tar remover should do the trick.