What would you do when you encounter a badly rusted nut and screw? I am trying to take the 8 nuts all along the undeside on the chrome trim on the front bumper, but they are REALLY rusted. I tried greasing and lubricating them... and penetrating oils didn't do anything.

I am thinking of the following, but I am afraid what my plan is, is a bad idea.

Can I just saw off the nuts and screws? Or will this cause a severe problem? I am pretty sure I can go out some place and find eight of the 10mm nuts and screws to replace them. But anyone else have a suggestion?