Safe DIY PCB etchant

Hello out there, I was wondering if anyone knew a safe, homemade PCB etchant other than the vinegar and hydrogen peroxide method. That produces copper (II) acetate and I don't have any use for it other than copper plating, and I suck at electroplating anyways. I would like to find a safe, homemade copper etchant that is easily disposed or can be reused for something.  Thanks, Sam.

Ignore if you've already seen this one:

Make 10 Etchants for Copper Printed Circuit Boards

That one is good I found it entertaining.


cupric chloride works well and is easy to

There is straight salt and water electro etching.

I don't know how well it would work on a PCB, but it does a nice job on steel.