We've got a Keurig B60. I have no problem taking my time making my coffee, so I will hand-grind my beans and make a cup in a My K Cup. My DH, however, has to fly out in the mornings for work and can't be bothered. And he uses up three Tully's French Roasts a day (which is costly)! I was looking at the Pod Holster/Podmaker deal, but I can buy 108 K cups for what that solution costs.
Other than that first fine cup of coffee in the morning, I am most motivated by two things, in varying order: (1) saving as much money as possible and (2) cutting down (eliminating!) waste, especially plastic waste.
I started immediately peeling the stuck-down foil lids off the spent K cups, then rinsing them out thoroughly in very hot water before anything has time to light and grow on them.
My first experiment was to use them as little seed-starting pots; using a fine vermiculite or seed-starting mix and putting a bunch of them in one of those well-washed styrofoam meat trays you can't help but buy, I discovered that a little water will stay in the bottom of the K cup, keeping the filter and seed moist a good long while. I haven't tried yet to transplant from one of these little starter pots, but in the vermiculite I'm not anticipating any problems. I'm not sure yet how well these will bottom-water if you just pour water into the tray. But, actually, I think I'd prefer top-watering with only a little water plus some cushioning air remaining underneath the K cup's internal filter.
My second experiment was to actually try to use the old K cups to make coffee. (This after I'd run water through one used K cup to see just how much coffee can be extracted* before it's useless for that purpose. With DH's last leftover K cup each morning, I can make myself a decent cup, and that saves us some money. But the ultimate goal is to be able to make K cups that are easy for him to grab that don't cost so much. The following technique shows some promise.)
The used K cups don't, of course, fit in the My K Cup, so I had to find a way to prevent the grounds from getting washed out and into my cup. Well, those CVS Premium Cotton Rounds for removing makeup, purported to be "100% Pure Cotton," are perfect. Put coffee in the old K cup, lay a cotton round on top as a filter, put it all into the Keurig, close the lid, and brew. That little sharp tooth thing in the Keurig, which normally punches a hole in a K cup foil lid, pushes down on the middle of the cotton round to form a little indentation that helps guide the water through the K cup, not out the sides. When you remove the cotton round, you see the coffee grounds pushed up tight against the sides of the K cup and a little hole in the middle. The rounds are big enough that, even pushed into the K cup, one of them still covers the plastic cup and keeps grounds from pushing out the sides.
I tend to be chemically sensitive and was worried about what additives might be on those cotton rounds that would render them decidedly not food-safe. I've written CVS to ask, but I haven't heard back. If somebody here knows the answer, please let us all know!
Anyway, assuming the answer to the last question is what I want to hear, all I have to do is make up three of my recycled K cups in the evening as part of my get-ready-for-tomorrow routine. I'm hoping that if I line them up by the Keurig and remind DH that the filter tops are not stuck on, he won't scatter coffee grounds all over the kitchen.
(Oh, and if anyone from Keurig is lurking here and knows for a fact that this method will damage their machine, please tell us that, too. But I can't see how it could. It seems to work the same way as it always does, makes the same sounds, drives water through at the same rate, etc.)
Now, let's hear what other people are doing to recycle their K cups!
*When I was in Europe three decades ago, I had a lovely light dessert made by using strong coffee instead of water with unflavored gelatin to make jello; it was served cubed with whipped cream in a margarita glass and was so elegant. You still get coffee after you've run water through the same K cup three or four times, so I think I'm going to try using that weak-coffee water with some xylitol and maybe some other ingredient that will go well with coffee (chocolate ice cream, heavy cream, etc.) to make a similar lighter gelatin dessert. I just hate for anything to go to waste, especially as much as everything costs now!