If the blade is not bent badly(slightly out of line) then it can be straitened by eye, hammer and backing dolly or anvil-type surface. Make sure the rivets (if used) are not loose. If so discard the fan. As long as the blade has not been bent back past a 90 degree angle, heating it to a dull red and straitening it with a hammer and dolly should present no problems. The trick here is common sense, if the fan is damaged badly, throw it out. If slightly damaged, use your head. This is a subject that can get pretty heated. You don't want to fix a real mess and then have a friend or relative get a blade thru the forehead.
