Cleaning grip tape?

How are you guys cleaning grip tape on the board? I got sand and dirt that won't come off, so tried simple green and a toothbrush which worked decently.

 

check out grip gum

The Original Grip Gum

 

I got a few brass brushes and a sand belt cleaner rubber block from my local hardware store and it cleaned up the board nicely. Pro Tip: remove top cover on the board first then clean it off to avoid scratching the carbon fiber with the brass brush.