A few more thoughts,
You have listed a 9880, but mention green ink/color on the nozzle check. The 9880 does not have a green cart, so if you are seeing green, it's a bleed issue between other colors, which may be a damper issue. NOTE, if the printer was left for 1 year with ink in it, more than likely your problem is a damper clog. The dampers are not that hard to replace on the 9880 and I would look into that before a head replacement.
Windex, I would stay away from it, the inks are aqueous, and water will do the same thing. Windex has other agents that may or may not hurt the head. If you go back to the extra long post on this site about "the 7900 from the inside out", there is mention on one of the pages of a Epson cleaner used by the tech's that you can purchase. If you want to use a cleaner I would try that.
Your 9880 has two extra cleaning cycles, the Power Clean and whats called a SSCL, (super Strong Cleaning Cycle) I would try the Power clean option first, then the SSCL. I can't remember the steps for the SSCL, but you launch it from the Utility panel on your computer. Epson Tech support can step you through this. Both take a lot of ink. If you can't get a clean NZ check after both of these, then I would look to the dampers, and if that doesn't fix it, then the head.
Lastly, clean off the wiper. On the 9880, move the head out of the way, then look up inside towards the top. You will see the wiper, a long black rubber strip. More than likely yours is either worn out or dry and coated with old ink. Wipe it off with warm water and and lint free cloth. Look directly below the wiper and you will see the area where the head is parked. It's a multi color felt looking patch. Soak that with warm water also and then park the head back. The water may help to free up a clog.
Good luck, and hope you get it working.