A:Answer For over three years I've been refilling my 251 C, M, Y, BlK cartridges with dye based pixma ink from large bottles for canon ink tank printers, and a bottle of pigment based pixma black ink for the one 250-Blk cartridge my printer also uses. just punch a hole in the center letter "n" in the word Canon on the top of the cartridge then use a syringe to inject the ink into the cartridge through the hole. just insert it about 1/4 inch or so. if you top it off be sure to let it sit for a few minutes before installing. do not cover the hole you made as it needs it for a vent hole after you likely just obstructed the original vent channel that you can see if you pull off the label that hides it. I've never had a leak or a dried out cartridge. I've heard that each cartridge is ok for 5 to 8 refills each, or until you get smears. I've gone through about 15,000 printed pages since i started refilling I'm just now having to do bimonthly cleaning cycles, but more likely from the 19,741 total pages my MG5420 has printed, and not from the refilled ink, she is getting worn out. personally I would avoid using cheap ink and stick with the original canon pixma ink as my source. I did use a bottle of Epson Black dye based ink without any issue. lastly, be sure to NEVER mix up your dye based ink with your pigment, if you do just toss it out or you will either make a mess or clog you printhead. CLI is dye based and beginning with a P_ _ _ is pigment, PFI- , PGI- , PGBK, PG- and GI- as well. I've likely saved thousands of dollars in ink costs by refilling. good luck to you
