Presumably you mean that it doesn't function anymore, not that there is any structural damage. The obvious things to do are make a static prop out of it (as Excogitate showed), or to break it into pieces and use some/all of them as a part of another prop (or potentially on their own). You could possibly use the teeth as teeth to some creature, build a weapon out of it, turn the gas can (presuming it's gas operated) into some sort of spooky liquid container (a-la mad scientist, alchemist, or witch/wizard), etc. I'm not familiar with all of the parts of a hedge trimmer, so my knowledge of them only goes so far.