I heard about that - I don't quite recall (I may ask the person from which I heard it, when I meet him, but that's not likely anytime soon) - but I think it was filling the cartridge with the etchant - since the cartridge was never meant to contain a strong corrosive, it dies rather fast, but you can create a batch of medium-to-high quality boards this way. Just modify the printer so you can pass boards through it (or get a model that allows that. There are models you can run CD-ROMs through...) replace cartritge, print, flush with water and it's ready.

There are also laser printers that allow rigid media to be run through, this way you don't have to print the design on transparency/paper and then iron it onto copper, you just print it straight on the copper. These printers aren't cheap though.