Recycling used cooking oil (also known as FOG’s – “Fats, Oils and Grease”) is always the best option. Many landfills do not accept the substance, since in its liquid form it can contaminate water tables.
Pouring it down the drain is a leading cause of sewer backups for homes and businesses. Soap and hot water do not break down the grease; they merely carry it further down the drain where the water cools and oils begin to congeal in the pipes, eventually forming a wall of grease.