How to refinish this wood and aluminum...

My back door step could use some sprucing up but I'm not sure how to go about it. I would imagine the wood pictured is treated and the metal is aluminum. How would I go about resurfacing or finishing both these surfaces to get them to look some better?


The painted white part on the left is actually a different surface a couple inches below the unpainted wood step.


Thanks

Attachment 525786

Can you disassemble / remove it. Would be a lot easier to re-condition if you could have all the individual "parts" accessible in your workshop.