Homebrew PCBs

On Mon, 26 Jun 2006 04:32:44 +0200, John Popelish <jpopelish@...>  
wrote:

>> I'm considering using this combination as an echant and I was wondering
>> if anyone could give me some tips as to how to dispose of it safely
>> when I'm through with it.  Also, some tips as to how to tell when it is
>> all used up a I need to throw it away.  Any help would be appreciated.

> Get a box of washing soda (sodium carbonate) from the grocery store.
> Slowly add it to the expended etchant, till it stops foaming.  This
> neutralizes the acid and precipitates all the copper out as copper
> carbonate mud.  Dump the neutralized liquid down the drain and put the
> mud in the trash.

Also consider if you don't want to use the etchant to start a CuCl batch  
which can be regenerated forever.

ST