Homebrew PCBs

I don't know what to say about ionic contamination either, I have no
idea what it is ;)   How does it effect a board?  Does it rot the
FR-4?  If I'm just looking for a fast way to prototype PCBs, would it
rule out it's use?  I'm just looking for a _cheap_ way to do proof of
concept, and that $1.00/ounce is looking pretty inviting, but if it
messes everything up, it's expensive at half the price.
  I looked at Heraeus for powdered flux, but only found liquid and
paste.  I have an e-mail in to them to see if they have anything else.
Thanks
Richard
> 
> One of my friends tried that, but found that he was unable to clean
it, plus
> he also had ionic contaminants that migrated into the laminate. It
might be
> worth trying a few things, but the cleaning will be critical. As far as
> ionic contamination and resulting problems, I'm not sure what to say.
> Ron