Using a set of pry bars would work. I've even taken crank arms off with a big screwdriver and a block of wood. You could also use a couple of large chisels (the kind that are wedge shaped) to get them off. The amount of damage you do is up to you though, but take my advice and just get a crank puller. You go prying crankarms off and you can easily damage the square taper interface of the crankarm, which is designed to be a tight fit when its bolted down.

The crank puller pulls the crankarm straight off, without any side to side forces ruining the square taper.