· experts say cooking oil, grease, and fat should never be poured down the sink , especially after being heated in a pan during meal prep. Grease poured down the drain builds up inside the pipe and eventually clogs it. These are the best and safest ways to dispose of cooking oil that wont harm your pipes or the environment. · before you pour that hot oil down the sink drain , read this first. Oils and grease are in liquid form while warm, but will become a solid, jello-like substance after cooling; · although letting a little oil trickle down your drain can seem pretty harmless, the truth is that it can wreak serious havoc on your plumbing system. That’s because these oils are hydrophobic, meaning they don’t mix with water very easily, so they end up coating your pipes instead. Cool cooking oil completely and seal it in a container for trash disposal, or take it to recycling services— never pour oil down the drain or garbage disposal. Yes, it’s cool to change the oil in your car and maintain your vehicle at home, but properly disposing of the used chemicals is critical. This is what will mess up your plumbing. Never pour motor oil or other automotive fluids (including anti-freeze, gasoline, and solvents) down a drain in your house or garage. Running hot water might help push the grease further down the drain , but it wont completely solve the issue. · oils like olive oil and canola oil may not solidify at room temperature, but plumbers still advise against pouring them down the sink. This is particularly common when cooking meat since the grease solidifies as it cools.