Homebrew PCBs

mark.mickelsen 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.