Quote Originally Posted by Y33TREKker View Post
A c-clamp is usually the easiest option if you have one. If you don't have a flat piece of metal like shown in the picture, a wrench laid across the brake piston will work too.

I use that method but instead of the flat plate, I use a deep socket to push against the piston (of course, it's a little more tricky to do it whilst the caliper is still attached to the vehicle by the brake line). I like my old vice-grip caliper compressor but can seldom get it at the right angle with newer calipers.