Aluminum brightner that comes from local big truck dealers (Truck Pro, Fleet Pride) works reel well on all aluminum surfaces and if you really want to clean aluminum use muratic acid, Be very careful with that stuff. You can dilute it with water and it comes from your local Ace Hardware.
"Alumabrite" is what I have bought locally and used on my boat. I have bought it at Mill and Mine Supply on Dayton Blvd and Walter A. Wood on Rossville Blvd.
I'm sure Truck pro has it too.
BassAddict is right about Muriatic act but if you use it wrong it will etch the aluminum and make it catch more dirt and make it harder to clean in the future.
Streaking can be a real problem in chemical cleaning. Work you way from the bottom up and rinse rinse rinse to avoid streaking. Use fine steel wool or scotch pads on stubborn areas.
"Mothers' aluminum wheel cleaner from any auto parts store is good for polished aluminum. It also works pretty good on those dull plastic headlight assemblies.
Mix up some Tide Washing powders in hot water with a pretty strong mix and brush it on. It will cut the "Crud" off the pontoons. After it sets for a little while clean it a second time with a rag or sponge and the tide mix. You will be amazed. Then use your aluminum cleaner to finish the job. Do not use any type abrasive scrubbers on your aluminum or it will be dull forever. If you have rust spots or bad stains you can use "Fast Orange"hand cleaner on a damp sponge or rag and take the stain right off without damaging your surface sheen. I use Fast Orange to take stains off my solid white saltwater boat.
