Lead

When, in Alan Grant's Smallville novel, Dragon, Clark Kent fights a meteor-empowered monster, the monster's enhanced strength is no problem, except when, because of meteoric emanations, Clark temporarily forgets and loses his powers, but the fact that the monster's body is infused with the radiation is a big problem and there is a neat solution.

Clark already knows that lead blocks not only his X ray vision but also the meteoric emanations. The text has already described some of the treasures in the Luthor Castle, including a large Byzantine lead cross. Remembering this, Clark, using super strength, pounds the cross into flat sheets that he can adapt as body armour which he must afterwards discard. Thus, he has stolen and destroyed a work of art but in order to rescue Lana who had been kidnapped by the Dragon.

Some of us are old enough to remember when, to handle Kryptonite, Superman wore lead armor that had to cover his entire body including his eyes. Unable to see out even with X ray vision, he wore a TV camera on the front of the armour and an aerial on his head and had a TV screen in front of his face. It is good to be able to remember those days but there have been better versions of the story since then, most notably John Byrne's Man Of Steel mini-series and the Smallville TV series.