Aluminum is highly malleable, which makes it easy to work with but also easy to accidentally bend. If you do inadvertently bend a piece of aluminum, don't assume it is ruined and throw it away. With the right tools, you can easily straighten aluminum yourself rather than spending money on a new piece of metal.
Bend the aluminum object as straight as you can with your hands. Depending on the thickness of the aluminum, you might not be able to bend it at all.
Lay the aluminum object on a flat, solid surface, like a concrete floor. Use a heat gun to warm the part of the aluminum you wish to straighten.
Straighten the aluminum object with your hands as it begins to heat up. Keep adding heat and bending it until you straighten it out completely.
Hit the heated aluminum with the rubber mallet to remove any bumps. You can now reuse the aluminum.