Carts repeatedly lost to mold (?). What to do?

[The Hat]

I am using genuine Canon cartridges. And leaking/cross-contamination is an entirely new (and previously unknown to me) possibility. I had thought my yellow ink turning dark was definitely mould. Is there a way to be sure?

If you are sure your purge unit is functioning properly, then the only thing that would be causing cross contamination is the print head itself..

If that’s the case then you can kiss the printer good bye, because there are no more print heads available for that model printer for a very long time..