For the past five years or so, our five-unit co-op has encompassed a Lubavitch rabbi and his family. His five little girls, ranging in age from 1 to 12, have taken to paying us visits on Sabbath Saturdays, trooping upstairs in their modest long-sleeved dresses to chase the cats and play MasterMind and read my kids’ old storybooks. Other and I love their visits, but have some consternation. Hospitality is deeply engrained in us, and we cannot offer them food or beverage without polluting them. For nothing we normally keep in the house is kosher. And in any case, our dishes have not been maintained in kosher purity. Even water, when served in our impure glasses, is taboo. We’ve discussed this with the girls, who’ve advised us to buy some kosher cookies to solve the problem, or have grapes on hand, since they require no cutting, as apples would, with one of our nonkosher knives. Anything that touches something that touches something that touches something that touches you can contaminate you. It’s like cooties, an affliction I haven’t had since I was the age of the little girls themselves.