Aluminium is treated generally with an anodised coating that is applied through an electrolytic process to protect aluminium surfaces. You can get it in clear as well as a multitude of colours.
A firm specialising in anodising will have generally the equipment to remove any oxidisation but beware. Any surface damage will be removed leaving the surface uneven so you may want to prepare the items yourself leaving the firm to do the final clean before anodinsing.
One note of caution it to ensure that the insides of the fork sleeves are not anodised as this may well prevent the fork stanchions from sliding into the sleeves.
