if you can get a socket around them still (assuming you have yet to round them all to heck) get the socket glowing hot with a torch. I mean really hot and then let the socket sit there for a min. Then try it. Be carefull of using the torch on the car. You may want to but the nuts back on and drive to a service station that has an impact wrench. The vibration works most of the time. OR.... Get a pair of big vice grips and a hammer.