When it comes to your kitchen sink, the only thing that should be flowing down the drain is water. In reality, you might call that a pipe dream. So much gets washed down our kitchen drains, from food particles to soap or the occasional spoon

But despite these drainage mishaps, there are a few things you never want to wash down the drain, even if you have a garbage disposal. Not only can you end up with clogged or damaged pipes, but you’ll also have to deal with an unpleasant, lingering odour.

Fats. These are some of the worse substances you can wash down the drain and into your home’s plumbing system. Once fat hits those cold pipes, it starts to congeal, becoming hard and waxy. Over time, fat will build up in the pipes, resulting in total blockage of your drainage system.

High-fiber foods. Items such as asparagus, carrots, celery, corn husks and potato peels can spell trouble for your kitchen drain and disposal. Fibrous strands can get caught in the grinding plate of the disposal, which then build up and lead to a clog. Additionally, high-fiber foods simply don’t wash away well. Fibrous strands can tangle and clump together, causing drainage issues.

Seeds. Even the smallest seeds can cause serious problems. Large seeds (peach pits) aren’t going to go anywhere and may end up damaging your disposal or getting caught in your pipes. Smaller seeds are also a challenge for disposal and can become lodged in the grinding plate and pipe bends.

Starches. Foods like pasta, potatoes and rice are heavy, and they absorb water. Because of this, starchy foods can become a thick mess inside your drainage system, much like fat. They can settle and accumulate, leading to — you guessed it — a clogged drain.