ive just realised what area i've posted this in (sorry mods, feel free to move it to the how to guides area
)
Get a brand spanking drill bit, and make sure it is the same size as the diameter of the original non-formed pop rivet.
Start slow with the drill, and that way you should not get it turning in the hole. If you do get behind and clamp the tail with a pair of pliers or mole-grips.
The sharper the drill bit the better.
Are they steel or aluminium?
hard to tell as they are dull and tarnished but not rusted, so aluminum?
its the turning that was concerning me which why i initially thought about going bigger than the rivet but theres not enough metal to afford this, i was also told to use a blunt bit rather than a sharp one which didnt seem right to me either but apparently it stops twisting too
you saying sharp sounds better though, would you pilot it first with a smaller bit or just go straight for a matching size? (as in the size of the rivet not the squashed end)
then i guess its a case of just knocking the tails out?