Is one allowed to use the liquids which was squeezed out of the fish?
Introduction to the Melacha (Part 2);
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...
opening up a double knot "במקום צער" (very annoying);