Long story short I took some simple green to a toothbrush and brushed the front of my valve cover. After drying it appears as if the paint has dried out.

I have tried taken some damp microfiber towels to clear away any excess simple green that may have been left behind, but to no avail. Once the water dries up again, it has that nasty dried up look to it.

Any suggestions on how to get rid of this? I was thinking maybe wd40?

 

Simple green is a no no on aluminum (straight or strong concentrate) unless you rinse it really really really well. Dilluted it is not to bad but not that good a cleaner at safe levels for aluminum and I even diluted I still wouldn't use it on a car. It as actually eaten into the aluminum and corroded it. Not sure you can do much but refinish the valve cover...

If you are looking to wash the motor, Adam's APC Straight or P21S are great to use and you get fantastic results with little effort, and no chance of corroding the aluminum.

 

I had good results with Spray Nine, I think you need to clean off remnants of the Simple Green, sounds like some deposits remain on the cover. I don't think SG has done anything to the paint it has just left deposits behind which need to be cleaned up. Do a test spot using Spray Nine, CLR, or Rubbing Alcohol to see if they clean up the deposits.

 

Maybe not the recommended stuff but I've been using BlueMagic convertible top cleaner on mine and it looks real clean and real red.This stuff has a mild conditioner in it as you can feel it when you rub a little between your fingers.I don't spray it on the cover but on a cloth and then wipe.Then use the clean side of the cloth to buff.