Blech & Co.

A blech (from the Yiddish word בלעך (blekh) meaning "tin" or "sheet metal", alternatively from Middle High German or Standard German "Blech", meaning tin or sheet metal) is a metal sheet used by many observant Jews to cover stovetop burners (and for some, the cooker's knobs and dials) on Shabbos (the Jewish Sabbath), as part of the precautions taken to avoid violating the halachic prohibition against cooking on the Sabbath.