Thanks for the reply. However, the guys in the link used some kind of tiny damper attached to the lid of the cart on the inside and therefore didn't need the sponge. I'm mostly curious what it is that they used.
Hello, you said you removed the HP sticker on top of the cartridge, did you replace it, or use tape to cover the top?
If it's not properly done, you could block the air vents that let air into the cart as the ink exits while printing. If the vents are blocked, you might only get a couple of...