הChelek 5
- If you ever find a pocket of flour in a baked matza — do not put it into gravy. If you do, it will turn chometz and the food will become ossur b’hano’ah. (Siman463 — MB )
- Saliva from humans and farm animals can cause grain flour to leaven. Steam can cause grain flour to leaven. (Siman466 — ShA , — MB )
- The poskim argue about dampness that ‘sweats’ from walls. Lechatchila, do not use flour that became wet with such moisture. (ShA — MB )
- Using a gentile’s chometz medicines to heal illness or wounds is allowed if there is no alternative way. You do not own the chometz and the issur hana’a is only mid’rabbonon. (MB )
- If there is danger to life you are allowed to benefit from chometz and even eat it if there is a chance it will help. If there is no danger to life even a crumb is ossur. (MB — ShaH6)
- The following fluids can leaven just like water: (1) dew; (2) urine; (3) fluids from the nose, mouth, eyes, and ears; (4) runny bowels. (ShA — MB , )
- The following fluids do NOT cause chometz: blood, milk, fat, bile, sweat, excrement. (ShA — MB , , )