Erasing original owner data on PowerPC G3 iMac Gen 1 running MacOS 9.2.2

Since this is Mac OS 9.2.2, you should not have different user accounts.

Without a bootable system CD, you would have to manually erase personal files, and all otherwise not needed files and applications (at the main hard disk level and in various folders). Move to the Trash (Wastebasket), and empty the Trash via the Special menu.

However, just emptying the Trash is not sufficient. You can use a special utility like the free Burn 2.5 from Next Wave Software to overwrite/erase free space (after having verified the hard disk via Disk First Aid).

Also, open the System Folder and check for personal files. For example, most if not all files under Preferences can typically be deleted. The System Folder as such, with its System and other necessary files/folders, must stay intact, though.

StuffIt Expander should be on the Mac OS 9.2.2 Bondi Blue iMac G3 already. If you need to download a utility (such as the aforementioned Burn 2.5) or something else via a modern Mac or PC, keep the MacBinary (.bin) or BinHex (.hqx) encoding unaltered until on the Mac OS 9.2.2 iMac G3. Do not try to open/decode/decompress anything on the modern computer. You should be able to use a standard USB flash drive for the transfer to the iMac G3. Once on the iMac G3 hard disk, drag the .bin or .hqx file onto the StuffIt Expander program icon (do not just double-click on the file).