I think aluminum discolors in the dishwasher. Doesn't affect performance, just appearance.

From Surfa's:

Vollrath Cookie Sheet Aluminum 17"x14"
Item: 32392

Vollrath Cookie Aluminum Sheet 17"x14". Heavy-10 gauge 3004 aluminum heats rapidly and evenly. Available here in an aluminum finish.

Rated Highly Recommended in the June 2005 issue of Cook's Illustrated.
Please note: Due to a printing error, Cook's Illustrated lists this as "steel", however the actual item rated is aluminum.

Susan

Has anyone else experienced this problem?

It makes them look really ugly and nearly impossible to clean afterwards.

I don't have that brand, but I don't typically put aluminum items in the dishwasher, either (even if they do say, "dishwasher safe"), so can't help much. I find using parchment paper on pans yields good baking results & makes cleanup a lot easier.

I believe chlorine can react with aluminum, however, and if you used a dishwasher detergent that contains chlorine bleach or have heavily chlorinated water, it could discolor the pan. You might want to check with the manufacturer for an opinion. Good luck!

Aluminum will indeed discolor in the dishwasher. I also don't like the feel of the pan either. The abrasives in the detergent I think put fine scratches in the pan. It may not affect the performance, I just don't like the way they react to the dishwasher so I just clean my pans by hand.

Shannon

Anolon came out with the titanium pans so they could go in the dishwasher, their standard aluminum is not to be put in the dishwasher, so you cant blame the vollroth product