Out-Standing! I think yer holding back on us; that looks like you've been doing this for a while. But no cookies for you until you replace that tray. Come to think of it, cookie sheets might be cheaper than a sheet of Al.
I've bought some stuff from TM Technologies in the past. They have great on-line tutorials. Here's one on annealing aluminum that should come in handy > http://www.tinmantech.com/html/alumi..._continued.php