Joji,
I scrubbed it with a Scotchbrite pad and Simple Green and then hosed it off.
Let it dry and cleaned with alcohol in a spray bottle. I am using Dupli-Color with ceramic
engine paint, it does not say to use primer. It said it’s for manifolds etc… I will be trying to duplicate the Lotus gray since it has a blue tinge to it…..hope to try that tomorrow and will post results…