In this video, a Canon print cartridge is opened up and revealed not to contain the meagre 11.9 ml (0.4 fl oz) of ink it is advertised. The proposed solution is to buy a printer designed to be manually refilled with bottles of ink (such as the featured Epson EcoTank ET-2850), though it has only been tested briefly.
Even then you’re supposedly paying for usable ink. I don’t think the ink will all drop down from the foam.
This can be tested still.