Introduction to the Concept of עובדא דחול (Uvda d'Chol) in Relation to the Melacha of M'AMER;
Performing a service when it doesn't necessarily have to be done on Shabbos.
מבטל כלי מהיכנו (nullifying a vessel from its normal usage). Putting a כלי (utensil/vessel) under candles to catch oil, to catch the candle and...