Well, I do not get rid of them. At least not quickly.
The mixtures can be reused many many times before they wear out. I have seen an intransparent bottle of caustic soda on a professional electronics lab and its still used.
The method you propose requires very expensive inks, and I do not know if there is any of these including the heads for ordinary printers. I think if one is to pay so much, he could send it for manufacture on a professional lab.
I am still sceptical about the printer method I reffered to earlier, it seems so much quicker and easy, and the only way for microwave PCBs at home...?