rounded

One of the torx bolts is completely rounded on my engine cover/case. Whats the easiest way to get the at least the head of the bolt of so the case can be removed? I've tried getting mole grips around it but the bolt is indented making it impossible for the mole grips to grip the bolt. Thanks

I am in the prcess of taking my cylinder head off for a head gasket replacement, however I am now stuck because I have managed to strip one of the allen bolts. I have tried heat and mole grips but no joy. I need advice on the best way to remove the bolt without damaging the chain cover. :wallbash:

Went to do an oil change on my 190E, all ready to go, got on the ground socket in hand only to find some fool had put the sump nut on with such force the head of the nut was a cylinder and same fool did so without putting a copper washer behind the nut :mad: - end of rant. Tryed everything...