I first sprayed it down with an all purpose cleaner (like simple green) and whiped it down with a paper towel .....i did this to just get the surface dirt off.
Then use some of those mr clean magic erasers and a bowl of water.....following my scrubbing with wiping up the dirt with a clean paper towel.
I actually am using some knock off generic erasers I found at walmart...same price, but you get 6 instead of 4....and they are bigger too i think