Just picked up a 1976 alumacraft 14.5ft v-hull, trailer, and bow foot controlled tr. moter for a couple hundred bucks.  It is going to be a winter mini bass boat project for me, until then I am going to hit the water with it the way it is.  My question is what is the best way to cleanup unpainted alumanium?  It's not real bad just dingy and marks from the water line.  Any insight would be appreciated.

If it's just water-related scum, etc., try something like Simple Green (available at Wallyworld), or Castrol SuperCleen (available same place in automotive dept).  I've used the Castrol product, mixed per instructions on the jug, and once it's sprayed on you can see the crud running off the boat.  Spray it, let set for a minute or two, then take a scrub brush to it.  Should come squeaky clean.

I'm doing the exact same thing.  After a bit of research I settled on 3M Marine Aluminum Restorer and Polish.  I'll let everyone know how well it works.  If you want I can even sell you what I don't use - I doubt I'll use much on my 14' jon.

Simple green- Fantastic on mildew also (boat cushions,etc)  

Superclean-AWESOME STUFF!!!  My brother owns an auto body shop and this is on their latest and greatest list.

You can also buff that boat if you want it to look like chrome but the look doesn't last very long unless you treat it with a product called "sharkhide"

Sharkhide. Here is the link:

http://www.sharkhidemarinesales.com/