I would like to first suggest using jumper cables from your car. But if you have none, go to your spouses (I did not say wife's!) car, and randomly pull a wire from the engine bay and use that. j/k
Seriously, joke mode off, any wire small enough to fit in the hole should do. The ends need to be bare. As a former service engineer, I'll say use an insulated wire. It needs to be small enough to fit in the hole. Something stiff will not tend to snake around in there and hit another pin or cause smoke to leak out (bad!). Especially if the wire is the soft stranded type, don't stick it in 1/2", just go in enough to touch the pin. Solid core wire would be preferred, but any if you are careful. The voltage and the current flow is very minimal and it won't take much wire to handle it. Larger gauge will just be easier to hold onto and guide.
I would recommend the paper clip, but as soon as I do, some throwback from the 70's in a polyester throwing lightning bolt from his finger tips like the God of Thunder will static damage the poor phone, and I don't want to be responsible for the senseless murder of an innocent electronic device. An electrical taped paper clip would probably safer, and someone suggested in a different thread to ground yourself to a plugged in computer case, which is not a bad idea anyway.