Since the Chinese calendar is a lunisolar calendar, the last day of a year is also called lunar New Year's Eve (Traditional Chinese: å¤§å¹´å¤, Pinyin: dÃ niÃ¡nyÃ¨, translated: old, large, huge, major, important year's night).
While aluminium doesn't rust, it often becomes dull from corrosion, and is often encrusted with brake dust, calcium, lime, tarnish, grease, oil and hard water stains. Simply washing it off will not work, you need something stronger and more effective to do the job.
Powder coated aluminum is aluminum that could be extruded aluminum, that is cleaned, coated with a colored plastic powder, and then baked so that the plastic powder melts and forms a smooth, nice and even coat of colored plastic over the part. This is basically painting the part.