Homebrew PCBs

>Food coloring: good. I'll try it, too.

Available at any grocery store in the baking department used in icings.
(more for Stefan info)

>So far my old clogged Canon cartridge is not cleaning up. I may have
>to sacrifice one of the newer working ones.

I found vinegar (acetic acid) works to loosen old ink. You can revive
old dry dead ones by filling with vinegar and letting them sit, and repeating
a few times. Works good for cleaning the print heads too.

Dave