Hi Meork,
You can erase all of the contacts, calender entries, photos, etc, with each program one at a time. The key is to use the Options menu of each program. The contacts and calendar both have an "Erase All" command in the Options menu. The photos require a two-step process: use the Mark All command, then erase them.
But if you want to really restore your phone to the factory settings---for example if you want to sell it---then you can probably do it using the hidden Service menu in your
LG Voyager. Take your phone to a Verizon store and they should be able to do it for you.
Best regards, WiredNot