I've been using Inkjets since the mid 1980's and it seems to me most of the the comments about non-OEM ink clogging printheads is based on those first generation (fragile) printers. I have used only Canon printers since before the Pixma family was introduced. All have removable printheads and yes on occasion there have been clogs, but those were due to dried ink from lack of use. Currently I have a ten year old MG6220 and a Pro-100. I have been a refiller on all my printers and despite some really bad ink I initially used on the MG6220 I've never had a clog that did not respond by simply rinsing the printhead under running waster. The printheads are sealed and even immersion in water will not damage it. Just make sure it's either distilled water or low mineral content tap water. A few years ago I decided to take the advise of other experienced refillers and switch to Precision Colors Ink. That's all I use now and I can say that ink is very high quality and gives me results equal to or better than Canon OEM ink.