This is the ink I used: https://www.amazon.com/gp/product/B0783418P3 It was a bit of a challenge to find an oil based ink. It's easy to add too much ink to the ribbon. What I found works best is to take the ribbon out of the cartridge, stretch it out, then dab a very small line of ink down the middle of the ribbon. Then wind the ribbon back in to the cartridge, and let it sit for a few days. The ink will soak into the ribbon and even out (it helps having the ribbon pressed together in the cartridge for this). I'd also rub my gloved fingers along the ribbon to spread the ink out. That ink is somewhat sticky. On one cartridge I had to shorten the ribbon because it was getting stuck. Heating the "handle" side of a single edge razor blade with a torch and touching the ribbon made a nice join, almost as flush as the factory one. If you have multiple ribbon cartridges to choose from, try to pick one with the "gear" type ribbon advance instead of a rubber tire based feed. The tire tends to slip when it gets inky. If you do add too much ink to a ribbon, sometimes you can take another used up ribbon and feed it into the cartridge along with the inkey ribbon. Then the too-inkey ribbon will bleed some of its ink into the dry ribbon as they sit mashed together in the cartridge. I found adding WD40 to ribbons didn't do much besides making them smelly. -J