Used cooking oil should be cooled, sealed in a container, and thrown away with general household waste, according to waste experts who all gave the same advice when asked about the correct disposal method.
Pouring leftover oil down the sink can lead to blockages and plumbing issues, as fats and oils solidify when they cool and stick to the inside of pipes. Martin Garbutt, head of technical governance at Ding, told Express.co.uk: "Fats and oils are among the most common contributors to household drain blockages."
Proper disposal method for cooking oil
Garbutt advised letting fats or oils cool and solidify before throwing them away with household waste. The recommended approach is to allow the oil to cool completely, decant it into a sealed container such as the original bottle or a jar, and place it in the general waste bin.
Chris Houghton, home expert at HomeServe, echoed this advice: "Disposing of oil properly is easy. Let it cool completely in the pan, then pour it into a sealable container such as an old jar or bottle, screw the lid on and put it in your general waste bin."
For small amounts, wiping the pan with kitchen roll and binning it is sufficient. For larger quantities, such as after using a deep fat fryer, most household waste recycling centres accept used cooking oil, so checking the local council's website is recommended. Some councils also accept small amounts soaked into kitchen roll in food waste caddies.
How cooking oil damages plumbing and sewers
Houghton highlighted that the consequences of incorrect disposal extend beyond individual homes. He said: "Hot oil looks harmless because it's liquid, but as soon as it cools in your pipes, it thickens and sets, coating the inside of the pipework. Food scraps and other debris then stick to it, and over time, it builds into a blockage."
Even tiny quantities solidify as they cool and combine with other waste in pipes to create fatbergs, which Houghton described as "one of the most expensive and destructive issues plaguing the UK's sewer network." Once oil passes beyond a property, it combines with wet wipes and other waste to form fatbergs that can cause sewage to back up into homes and streets.
Jamie Campbell, operations director at Kane Enviro, added: "Used cooking oil should never go down the sink." For larger quantities, specialist cooking oil collection services will collect and process it commercially, with the key message being to keep it out of the drain at all costs.
