Next Winter I plan on building Revell’s 1/48 B-29. So I am trying to perfect a natural metal finish. I do not have an air brush, so I am stuck with Testors Metalizer paints from a spray can. I do not like really shinny aluminum airplane models. I think that an Air Force airplane should look like it’s been outside for a while. I also think that the aluminum finish should have a ‘grain’ to it. I think that the following technique gives the best Metalizer finish. I used a 1/72" scale P-38 that I bought for $7.00 as the guniea pig. 
STEP1: Paint the model with gloss black and sand out any imperfections. 
STEP 2: Apply three coats of Testors Metalizer paint. Let it dry and sand the finish smooth with 12000 grit sanding pads. The finish will look mottled, but that’s okay. 
STEP 3: Rub the finish with 0000 steel wool. This gives texture (grain) to the finish. 
Step 4: Rub the finish with a cotton ball to even out the texture.
paint an acrylic black gloss undercoat and mist on - light coats of the metalizer building it up. if it is buffable very gently buff with a soft cloth, but dont try to achieve a mirrorv finish. you cant and will only rub through the delicate paint.
I agree, it is not possible to buff MM Metalizer paint to a chrome-like finish. But I do not think that those paints were ever designed to do so.
I use MM Metalizer Aluminum Plate and Stainless Steel rattle cans to obtain different colored panels on my 1:24 B-24. After spraying a black base coat, I spray three coats of Metalizer paint. First I buff with a paper blending stick. Then I rub the finish with steelwool to give the paint a "grain’ just like the real thing. I think it looks great.
Some bare aluminum aircraft do have a pretty good shine. In peacetime I saw many squadron or wing commander’s aircraft that are kept quite shiny. Many civilian aircraft have owners who keep them pretty pristine.
And airliners in the forties and fifties put a lot of effort into shining their aircraft. Later, with the inflation of labor costs and increased size of aircraft they had to give that up, and went to painting or conversion coatings.
Also, prototypes in the thirties were really shined up. A polished BMF was considered an indication of company image, and a mirror-like finish was quite common on these planes.
I agree, it does look great! [Y]
Gary