We recently acquired a colour inkjet printer which required some intervention before it would print all the colours successfully so in the process of that repair there were two printer cartridges that were empty and ready to be put in the garbage. Knowing that others have scavenged ink from markers I thought I would have a go with scavenging the ink leftover in the two cartridges - a yellow and a magenta. You can see above that I have managed to bend back the top of the cartridge enough to access the inside (using a hack saw and a some pliers) and remove the sponges which were holding the remaining ink. I simply added some water and the ink dissolved into it. I filled two bottles with the ink I retrieved - a small one and a spray bottle. I did the same with the magenta cartridge and got two bottles from that as well.
Here are the papers I created in the process of removing the ink from the sponges. I made several backgrounds on glossy photo paper (10) and the rest was applied to regular bond paper in a variety of patterns. So I have a LOT of backgrounds to use for my creative projects and 4 bottles of ink that I can use for making quite a few more. It was a bit of a messy job and I should have wore gloves because my hand look like they have been "altered". I expect it will wear off in a couple of days. I am pretty happy with my little experiment and look forward to making up some cards with my glossy photo backgrounds.