AI Mode Answer With HP Instant Ink, the usual way to return empty cartridges is the prepaid envelope that comes in your replacement shipment. The postage is already printed on it, so you put the cartridges in, seal it and mail it. Most problems come from five small mistakes: throwing away the envelope with the packaging, forgetting to use it, mailing other items, letting empties pile up and assuming nothing can be done after cancelling. HP encourages returns so cartridges can be recycled, and HP's own recycling options are the place to check if your envelope is lost or your plan has ended. Quick Answer Keep the prepaid envelope from each shipment. Put only empty cartridges in it. Seal it and mail it. The postage is pre-printed. Lost the envelope or cancelled? Check HP's recycling options. Checked against the guide page and public HP community discussions in early November 2026. HP's programs change, so confirm current terms with HP. Nobody sets out to hoar...