Karlos Arguiñano warns against this habit many people have in the kitchen: "It's filthy."

Karlos Arguiñano has been on television for over 30 years, sharing his simple recipes with quality ingredients. But beyond strictly culinary dishes, the Gipuzkoan chef also shares everyday household tips.

For example, the chef from Zarautz has warned us how to deal with used olive oil left on a plate after eating or cooking. Or rather, how not to.

As reported by Men's Health magazine, Arguiñano has criticized the practice of pouring leftover oil down the kitchen sink drain, which he considers "a real dirty trick."

In addition to being unhygienic, pouring olive oil down the sink can contaminate many liters of water. In fact, one liter of oil can contaminate 40,000 liters of water.

And it's not just the environment that can be harmed, but also our own pipes: when the oil cools, it can solidify and accumulate in the pipes, potentially causing blockages.

So, what should we do? Well, we have to recycle it: we have to wait until the oil has cooled if it's been used for cooking. We strain it to remove any solid food residue and pour it into a sealed plastic bottle. Then, we take the bottle to a local recycling center or a specialized container.