Homebrew PCBs

>   I recently ordered some pcb's from abcfab, and on on the EBay page
>   describing the boards, Bill mentioned that there were a number of
>   cleaning solutions that would clean the copper, and that the
>   scotch brite scrub wasn't necessary.
> 
>   One of the cleaners mentioned was Tarn-X.

Don't ask me how I discovered this (I don't remember), but the
commonly available (in the US anyway) "Scrub Free" soap scum remover
intended for cleaning bathroom showers, tubs and sinks cleans copper
even better than Tarn-X, is less expensive and might be something you
already have around the house (it DOES work great on soap scum, too).
 It's in one of those pump spray containers.  Its active ingredient is
the same one used in Tarn-X, sulfamic acid:

http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=chem&id=11&query=sulfamic

Strange that it's not listed on the above NIH list since it does
contain sulfamic acid according to the label. For some reason, it
cleans copper more evenly than Tarn-X (I have a bottle of Tarn-X that
I don't use any more) and just as easily (sounds like I work for
them... but I don't). I spray a good amount over the board and then
swirl it around with a paper towel.  After the copper is bright
(doesn't take long), I rinse the board with tap water, dry it and do a
final cleaning using 91% IPA.  Other products that claim to be "scrub
free" tub and sink cleaners might also contain sulfamic acid, but I
haven't checked.

WB