The metal in most paperclips is electrically conductive, but not ideal. I don't know of any copper paperclips. Some guys have used nails, thumbtacks and even guitar string to make pogo charging work, so it should be good enough if it doesn't have a plastic coating.
You should be able to bend a springy shape, but will need to find some way to keep them dead aligned with the contacts. This phone not forgiving in the alignment.
If you intend to used the tip of the paperclip, you will need to sand it to a rounded shape to keep it from scratching or indenting the contacts and plastic housing.
Denso TP-100, SE T61z, Moto RAZR V3, Motoi576, Nokia E52, HTC Desire HD, Galaxy Nexus, Nexus 7, Nexus 5