Home and Garden - does anyone know the best way of cleaning cast aluminium garden furniture?

does anyone know the best way of cleaning cast aluminium garden furniture?

Power wash
bar keepers friend use a scrub brush and bar keepers friend the furniture will sparkle then rinse with your garden hose.
If it is unpainted, I would use steel wool, maybe SOS soap pads, which will not only clean it up but polish the metal to boot.

If painted, I would avoid power washing, which could take paint off. I'd just go with dish soap or car-washing soap and a scrub brush, one with bristles long enough to get into any detailing.
a jet washer,failing that bucket hot soapy water,and a broom dip it in and it works wonders,probilies be able to get a aliminum cleaner aswell,from many retail outlets,good luck,and happy scrubbing..
If it is really bad you could find some one ( a firm ) who can bead blast it or sand blast , otherwise a high power jet wash.
High pressure wash. If you look in the automotive section of a store you'll find good cleaners for aluminum.
You could always try a rotary wire brush in an electric drill, if you do this don't forget the goggles and face mask. It will be a bit messy but if done right the outcome should be what you are after.