[Getter-Done]

I drilled the center of the phillips screw head out with a twist drill a little smaller than 5/16" diameter.
Mine where very badly rusted.

I think I used 9/32 (but 1/4) would have probably worked also.

I drilled just deep enough to get too the back of the nut.
Then when I turned the nut with a wrench it broke off clean and no damage to the fender.