Been reading how-to on this site and tried the pop-a-top method on one of my PG-40 almost empty carts. When I pop the top I see a "white" layer of what looks like styrofoam....anyway, I filled w/14cc of ink (black) and am letting it sit. Should I tape over the nozzle area? The other PG-40 which is in the printer shows 1/2 full so I took it out and used the drill a hole method, put approx. 8cc of black ink in it and put it back into the printer...working fine so far. If the black 40's work, I will graduate to trying the color cart. next. Thanks in advance for the answer to my question above. Go Aggies!