Best Aluminium Cleaner

You could try a strong solution of Aluminum Prep, used to clean Al, prior to prep for painting, otherwise you may be into a very cautious try with the grinder prior to the AL prep.

Look at some YouTube videos for refurbishing aluminum wheels. Many use acetone (scares me). Most just buy new wheels. Aluminum is hard to bring back. I've had fair results with (surprisingly) Dawn dish soap and varying grades of buffing compound with an electric buffer, but they don't look new. Barrett Jackson (the car auction guys) is supposed to have a good restorer, but I've never been able to get it even from them.
For those who don't want their aluminum to get to this point keep them coated. I like WD40, CRC-656 or Boeshield T9 depending how close to the water it is. Some use wax.

There are special chemicals that they spray tractor trailer aluminum tanks with. They work well, but I forget the brand I used.

To protect or restore?

They sell products for both......On a yacht it's best to clear coat it to protect it, but the chemical cleaners work well. You can also buff aluminum diamond plate with a buffer and compound.

Same on wheels. I spent maybe 10 hours with a Dremel, a toothbrush and 4 grades of compound on my front wheel. Came out nice but not like new. Lost my ambition with my back wheel and just went at it with degreaser and Dawn and a toothbrush. Might go after the back wheel this summer and give the front another go before clear coating if I can't persuade my wife to spend a couple grand on new wheels for my B'day (unlikely). On a boat I have to think he's dealing with pitting and etching from salt. On better yachts I'd imagine those hatches would be stainless. Since they're aluminum I'm really wondering if the OP wouldn't just be better off biting the bullet and replacing the hatch. How big are these hatches?

If there is noticeable pitting, it might be best to strip, fill, and paint, or replace as NYCAP123 suggested.

I'm signing onto the strip, fill and paint option. Here's a suggestion for the prep work. My old Marine Trader has a mast mounted Raytheon radar with a complicated aluminum mounting bracket that was painted white from the factory in 1988. Paint was failing, and significant corrosion was present on several of the parts. In 2012, I took it apart and used a BRASS wire brush to remove the loose paint and oxide corrosion - some pitting was noted when I was done with the cleanup, but structurally OK. I brush primed everything with West 105/205 epoxy - the epoxy seeps in to the surface pits and sets up hard and remarkably smooth. I only needed one coat of epoxy. Two coats of Interlux Brightsides white, and the bracket still looks like new and cleaning is a breeze. Assuming West epoxy is as good a primer for brushed Awlgrip as it is for Brightsides, use Awlgrip paint and you will be done forever. Brightsides will only last a decade or two. YMMV.