Once in awhile I haul it outside add some soap and hose it off.
On a more regular basis (When I pull the liner out)..I take a spray bottle of my cleaner (dishsoap and vinegar water) spray and wipe with a rag. Seems to do the trick and I don't notice any weird smells anymore. It's not really that dirty seeing as a trash bag is in it..it's just more of a smell fresh thing for me.
I just tip it on the side to reach the bottom.