What chemistry is going on here?
http://i.imgur.com/C6hStFB.jpg

Specifically, why green?
http://i.imgur.com/A6zmLJM.jpg

The wife loves when I clean the toilets using the patented huckleberry
method devised by Oren of pouring concentrated pool acid into the tank, so,
she asked me to clean the pots and pans ("for once").
http://i.imgur.com/UOjeomJ.jpg

Being a believer in the magic of alchemy, I dutifully pour the HCL:
blob:http://imgur.com/f7bf8cd4-3abc-49dd-9b7d-16a5ae9c04a0

This muriatic acid bubbles and froths quite reassuringly, as if it's doing
something useful:
http://i.imgur.com/EqJPylY.jpg

But the end result is less than spectacular:
http://i.imgur.com/nmyISVG.jpg

It seems the metal *under* the baked-on crud was worn away, leaving the
crud!
http://i.imgur.com/kHCTfCe.jpg

On the inside of the pot, it just seemed to pit the insides like sandpaper:
http://i.imgur.com/XYnQF0P.jpg

The result of all that hydrochloric acid was a large vase of pretty green
"something" ... but what is this green something made out of?
http://i.imgur.com/O5R4g1t.jpg

More importantly, what is my next magic chemical to try?