Laurel,

Try this http://www.inkfilling.com/tonerrefillinstructions.pdf  see page 85.

The same toner cartridge is used in the HP 3505 & 3600 & 3800 ? Check eBay.

I cannot see a waste toner hole, as in the HP1600 & 2600 like mine - therefore the excess toner must be dumped in to an external waste toner hopper within the machine. Good luck.

Regards,
Ron.