I picked up this Stanley A6 plane today and would like to know a couple things.
1) It's base is aluminum and I'd like to know what the best way to clean it would be.  I understand that Evaporust shouldn't be used on aluminum.
2) What would it be worth, approximately.
Thanks in advance,
mike

) the best way to clean it

A) Don't
B) If you must, just a little soap and water, or alumnium safe glass cleaner*

Alumnium doesn't like being cleaned. almost every chemical known reacts with alumnium. The result is either dissolving the alumnium, or creating ugly insoluable compounds that refuse to come off the surface.
The other problem is, it is painted, and the paint available when that was made doesn;t really stick very well, you risk flaking off the paint if you clean it with almost anything.

As to the sides and bottom, first, it is cast alumnium, not machined alumnium, so, it isn't supposed to be shiny like the bumper of your car, it's natural color is a kind of dull gray..Using polish on it will probably make weird shiny/smooth spots...

Unless it is really ugly, I would do very little in the way of trying to clean the alumnium...

2c

* contains no ammonia or vinegar, only a butylated surfactant

Thanks, Rusty.  I guess I'll just use some warm water and soap on the aluminum. 
The blade and the locking piece I'll clean with some vinegar.

zomething about like... zissssss maybe?
  Its a mid century type. Not mint but it's probably a bit better then the rest of the plane
yours Scott

It has been my understanding that the aluminum Stanleys were war time production (WW II), and I doubt many were made.   I have one of the pocket planes in aluminum that I keep mostly because its unusual.

Quote from: Branson on July 18, 2011, 10:24:30 AM
It has been my understanding that the aluminum Stanleys were war time production (WW II),

Really? I kind of thought the latter SW period was when they started, but I could be wrong.
  I have a spare type 18 adjuster in my boneyard, but thought that might be too new?
  yours Scott

Quote from: scottg on July 18, 2011, 12:32:03 PM

Quote from: Branson on July 18, 2011, 10:24:30 AM
It has been my understanding that the aluminum Stanleys were war time production (WW II),

Really? I kind of thought the latter SW period was when they started, but I could be wrong.
  I have a spare type 18 adjuster in my boneyard, but thought that might be too new?
  yours Scott

Nope.  You're right.  I found this on Handplane Central:

Manufactured:    1925 to 1935
Length:    14 inches
Blade Width:    2 inches
Construction:    Aluminum, rosewood handle & knob
Finish:    None
Features:    A non-rusting, lighter version plane
Uses:    General purpose bench plane
Average Dealer Price:    $100 to $300
Average eBay Price:    $80 to $260

Vintage Tools has one for sale at $175, and there's one on eBay for $89.95

Patrick Leach's Blood and Gore page has unpleasant things to say about the A4 and the A5:

One of Stanley's dumber ideas, as can be inferred from their short time of offering, was the aluminum planes. The bed and frog on this plane are made from aluminum, which makes the plane lighter. This was the supposed appeal of these planes, that they are lighter than the iron planes. That, and that they weren't prone to rusting. Rosewood was used for the knob and tote. Despite all these swell features, the planes were a miserable flop.

These planes were produced at a time when nickel plating appeared on the lever caps. All the ones I've seen have the old-style lever cap, without the new kidney-shaped hole that was first produced in 1933. If you see one of these planes with a lever cap that is nickel plated and has a kidney-shaped hole, it's probably a replacement. The depth adjusting knob is also nickel plated, as well as the lateral adjustment lever.

They'd be useful tools if you were planing over your head all day, but not many of us do that. Since aluminum oxidizes easily, these planes leave despicable skidmarks (for lack of a better word) on the freshly planed wood. The planes - those that were used, that is - also tend to develop a very ratty look to them. The surface of the aluminum becomes riddled with dings and scratches making them blech to even the casual Stanley collector (well, maybe not all of them, but many of them for certain) - most of them take on a striking resemblance to the lunar landscape after being used. Those that are in mint condition have some appeal about them, but they still have look like of an aluminum pot or piece of foil. If you're collecting this stuff, make sure it's aluminum and not some iron plane in aluminum paint clothing - if the weight of the thing doesn't clue you in, a magnet will.

The aluminum planes were appreciably more expensive than the cast iron models. For instance, the #A4 cost $5.65 at its introduction, whereas the #4 cost $4.20 during the same time. Even back in the Roaring 1920's, consumers were smart enough to avoid a plane that cost over 25% more than one that did a better job.

You have to wonder if any heads rolled for this braindead idea? Lucky for us that Stanley didn't make a mitre box, or something like that, out of aluminum. Hey, wait a minute, they did! Let's just say that the company was going through a phase and be done with it.

One more thing.  The A6 was in production until 1938 -- three years longer than the A4 and A5.