One of my secrets... don't tell no one else.
Use a socket set and a rubber mallet or hammer, used gently of course. The sockets that have diameter step on the outside are better for this, but any should really do depending how you do it.
Just match a socket that fits now, do what you can and go up in size slowly till done. You should get the idea here, if not let me know I will explain in details.
Oh and yes there is a tool for this job too( forget the name ), but most people I know with any tools they already own socket sets too.
D.K.