When Rabbi Naftali Marrus does his spring cleaning, he doesn't use a mop. He rolls with the Inferno.

The Inferno is a three-and-a-half-foot-long propane torch Rabbi Marrus uses during the critical days before Passover to scour commercial kitchens catering to observant Jews and obliterate the smallest particles of bread and other leavened foods, which are forbidden during the holiday that commemorates the Jews' flight from Egypt.

Marching into the kitchen of My Most Favorite Food, a restaurant on Manhattan's Upper West Side, Rabbi Marrus runs his finger along stove tops, pokes his head inside the big industrial ovens, examines the coffee maker and inspects walls and floors. They have been soaked in boiling water and scrubbed clean with soap, detergents, degreasers and ammonia. Continued...