I need to remove a faucet head but It is so stuck I can't get it off?

I need to replace a rubber washer in my outdoor faucet, but the faucet is so stuck I can not remove it, I can’t remove the faucet head itself, and I can’t remove the packing nut. When I use my adjustable wrench it just bends the metal of the nut completely and rounds the edges. I also tried two wrenches. The nuts have been painted over too. How do I get them off!