I'd be very careful using anything too aggressive to try and clean the surface. Start on one area with something like WD40 and a fairly non aggressive cloth. If that doesn't work try car wax or T-Cut, but again be careful, I don't know how thick that anodise will be. It should be just fine, but baby steps would be good.
If one product doesn't work just try another gentle offering, so if WD40 does nowt try all surface furniture polish etc.
Upt'North.