> Na2CO3 is somewhat cheap but it's still an extra cost Here in Holland it is sold cheap in every supermarket. But you can use NaHCO3 or NaOH if you like that better. And wait for the stuff to settle down instead of filtering. Or just electrolyse the copper out... Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: www.voti.nl consultancy, development, PICmicro products -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu