I don't know which nuts are getting you so frustrated, but I remember
one that nearly defeated me.  Frozen, rounded and nearly inaccessible.
I did succeed in getting it by using a sharp wood chisel and a hammer to
split the nut (Then of course I had to regrind and sharpen the chisel).

For what it's worth.

'80 Vanagon Westfalia
John Jensen, Mudbug Pottery
mudbug@toadhouse.com , http://www.toadhouse.com