This 4-pack includes Inkedibles cleaning cartridge (unclogs printheads)s for use with Epson printers that utilize the Epson T220XL120, T220XL220, T220XL320 and T220XL420 ink cartridges. These cartridges are filled with a specialized, food grade, cleaning solution which is great to help unclog printheads that may have become clogged due to non-use of your printer. Edible inks are made with water-based food coloring, they include sugar and color. If you leave the printer idle for too long, the liquid from the cartridges may evaporate slightly, leaving behind deposits which can crystallize and clog up your printer's print heads. By turning your printer on and then off once a day, your printer is primed to do a cleaning cycle and keeps the inks flowing through the print-heads, preventing clogs. If your print-heads clog up due to non-use, you can instal one of these cleaning cartridge (unclogs printheads)s and run a print-head cleaning cycle in your printer and print a few pages to get the cleaning liquid to run through the printer. Then switch back to your Inkedibles edible ink cartridge and get back to printing. NOTE: for significantly clogged printheads, the InkEdibles printhead flush systems may be required as those provide a more forceful cleaning. Do NOT use cleaning cartridge (unclogs printheads)s or cleaning solution from sources that do not designate the cleaning solution as food grade. Inkedibles brand cleaning solution is food grade and intended to be used on a printer that is dedicated for edible ink printing.