The environmental contamination caused by waste toxic metals and their acidic solution could be inhibited in solidified systems of activated kaolinitic clays. Low-temperature synthesis of alkali-activated clay generates a siloxo-sial amorphous polymer network, which excels in its behavior of netting the toxic metals in it. The setting of inorganic polymers occurs at normal laboratory temperature and pressure. The obtained solid matter locks waste metals (copper, nickel, and cobalt) in the formatted network. Natural kaolinitic clay is also a waste product of clay mining, owing to its higher content of coloring metals-iron and titanium.