The aluminum is very easy to bend, you just want to be gentle while doing it. Rest the convex side horizontally over your thigh. Put one hand on each end and with minimal force push down evenly with both hands. Check for straightness, then repeat until you are satisfied.
I bent and straightened a mis-cut plate to show that this works. Creasing the plate requires a lot of force. If you follow the method above, you will hurt yourself before you hurt the aluminum.
