I once work for a Jewish kitchen during their holiday dinner and the lady that hired me told me to not start the dishes until they all left the building. I was told I had to wash the dishes by hand with a huge rock of Gibraltar in the water basin. I sort of got worried because I knew by hand it would take several hours. The friggin rock didn't make things easier. Well after everyone left, the lady in charge took the rock out and stash inside the dishwasher machine and said "There! Now it's a kosher dish-washing machine!"