Air duster is ok, miniature vacuum cleaner attachments for outsides is poss better, see ebay. Normal vacuum crevice attachment for bellows folds may do. Lightly damped soft cloth on outsides only, DO NOT GET ANYTHING WET - ensure bellows even tho' they appear dry, is allowed to fully air dry before reassembly/playing.
If going under the bonnet be ultra careful not to catch reeds/reed valves or disturb pallets.
When the hard work is done, dry soft cloth with Pledge furniture polish - spray on the cloth, not on the instrument - on exterior.
NO OIL, NO WATER (other than the LIGHTLY damped cloth). Did I say NO OIL?