TreoI 800w - how to delete all contacts on phone itself not using ActiveSync

[KBphonetweak]

I bought a used Treo 800w and installed Opera Mobile 10 and Skype for Mobile without suspecting the previous owner left tons of phone contacts! I hope to avoid doing a hard reset. I do not have Outlook and do not plan to sync contacts.
Does anyone know the filename of the phone contacts database and where to find it on the phone, and could I jut delete it?