I bought a pair of quarter sheet pans in the summer, and one of them has developed an odd problem.  It has a grayish black coating that seems sort of like graphite was rubbed over the pan.  It will come off on your hands, but at the same time, I cannot rub or scrub it off completely.  It seems to be getting worse as time goes on—to the point I’m ready to throw it out.  It also seems to be worse after I run it through the dishwasher, but the other one is not affected in the same way.  It says they are dishwasher safe. I pretty much always cover them with foil when I use them anyway, and I can’t think of anything strange that I would have baked on them to cause this. 

Does anyone have any idea what this is or has anyone experienced something similar?

http://www.amazon.com/Chicago-Metallic-Commercial-Small-Cookie/dp/B0009WXW9U/

Hmmm… I’m surprised that they are dishwasher safe.  I never put aluminum in the dishwasher because it oxidizes in there (sounds like that’s what is happening to yours).  Have you contacted CM?  I would if I were you.

Yes, I think you’re right.  I didn’t know about this.  Apparently, the detergent in the dishwasher can cause this—doesn’t sound like there is a way to clean it either, barring industrial strength products.

There is a product you can purchase that won’t eliminate to color, but will lessen the yucky feeling of the oxidation.  It’s called Maas Metal Polish.  I buy it at Wal-Mart, but have also seen it for sale in drug stores.

Thanks, I will look for some tonight!

Matthew, I am afraid the pan you have is not 100% aluminum, but instead a steel pan coated with aluminum.  They call these aluminized steel, or aluminum anodized steel.  These pans are somewhat heavier than 100% aluminum pans, and a magnet sticks to it.  There are MANY “aluminum” pans that are also aluminized steel instead, like bread loaf pans, 9” rounds, etc.

So when you run it thru the dishwashwer, or when you scratch or rub it from regular use, it will graphite as you indicate.  Also, if you use something acidic on it, the aluminum will wash off, thus the steel shows thru (black spots).

A 100% aluminum pan, like the Magic Line rounds will not graphite, instead, it chips off.  A magnet will not stick to it.

Alumized steel is much more inexpensive than solid steel.

The maas metal polish did the trick.  They look the same, but somehow it keeps that black stuff from coming off on my hands and they feel smoother.  Thanks!

Oh good… I’m so glad it helped.  Works great on all kinds of metal .