Rub it with iCrap
In all seriousness if iclear doesn't work, the official iCleaner is something i can personally vouch for, i dont jsut use it on ipods...i use it on anything, it even has a scratch remover for the metal back and deeper scratches on the front of ipods
as far as anodised aluminum is concerned im not sure...but buy it anyway
srsly, i sold my ipod video for full price to get an ipod with decent battery life brand new on ebay after id had it for a month....the buyer thought it was brand new