Best cleaner for dirty gelcoat ?

[Shawsee]

I use Castrol SuperClean, it comes in a purple bottle. I use that stuff on everything from my ATV's to my truck and even the V-20. Just have to be careful to only do small sections at a time because you don't want to let that stuff sit for too long. It does work great and no scrubbing needed, spray on let sit for a couple of mintues then hose off.