Can aluminum be used in microwaves?

You should never put any metals in the microwave at all, unless it is pre-packing for a microwaveable food product.

Most metal items will act as a conductor for electricity in the microwave, causing sparks. Particularly if the metal is pointed at either end (ie cutlery). The microwaveenergyis reflected back and forth by the metal, causing burning and in some cases, a small explosion that can send glass and metalshrapnel flying overtheroom, like a military fragmentation grenade.

Aluminium which comes with microwaveable meals are designed so they can safely be placed into microwaves. They are thin and have been adjusted so that they cannot reflect microwaves.

Only placealuminiumin the microwave if the instructions on the food product say so. Otherwise - don't.