Also known as Muriatic acid and used to clean mortar off bricks. Many years ago I burnt potatoes rather badly when I forgot they were on to boil and could not remove the mess from the pan so decided some muriatic might just do the trick since it is basically the same as the acid in your stomach that dissolves food so well. What was left of the aluminium saucepan was a sight to behold but gee it gave off such lovely clouds of billowing white smoke before it ate right through. I also did it in the middle of the lawn which took some time to recover. But hey, that was over 40 years ago so I think I have been forgiven by now.
