Dirty Rocks

Hope fully, you meant muriatic acid, a weak form of sulfurric acid,
readily available at swimming pool supply houses or the hardware
store and often used to clean sidewalks and other
carbonate-containing materials. 

Well, I don’t exactly agree…

Muriatic acid is a concentrated form of hydrochloric acid. On
contact with concrete, it turns yellow and starts bubbling, eating
the concrete. On contact with steel, it corrodes the steel
instantly. On contact with skin it eats through all layers
instantly. It is nasty stuff.

If you must use it, be careful — dilute properly, and avoid all
physical contact with the acid and the fumes!

(swimming pool operator)