Well-established fact: K-Cups are wasteful, and are difficult to and usually are not recycled. While there are many alternatives to them if you must use a Keurig brewer, some people will continue to use them.
I’ve provided instructions on how to refill used K-Cups; not a truly tasty option in my opinion, but no worse than the original. In that post, I even came up with an unusual use for them once you’ve decided they have no business being filled with coffee again.
I recently came across a post on “Can I Recycle This?” which had many ideas for re-purposing used K-Cups, including tiny freezer Popsicles, bead storage, and many craft items. If nothing else, the whole site is worth a look for ideas on how to recycle or repurpose just about anything, from eyeglasses to medical tubing.