Homebrew PCBs

Ted Huntington wrote:
> Can Ammoinium Persulfate be poured down the drain?
> 
> Ted

Perulfates are unstable and will decompose to sulfate + 
acid. Of all the talk about morals of pouring etchant down 
the drain, it is only the copper loaded solutions which are 
considered harmful to the environment.
If you are only doing a small PCB every month or two then 
I'd just pour it down the drain each time. If you got a 20L 
drum of spent etchant then that's a different story.
One option is to etch in a small tray and then immediately 
dispose of the used etchant it into a 20L drum (correctly 
labeled) and worry about it another day when it drum is full.