We like to think of drains as some kind of magic hole that makes things disappear. As convenient as that would be, unfortunately, that’s not how they work—including those attached to kitchen sinks with a garbage disposal, utility sinks, bathtubs, and showers.

To avoid having to unclog your drain, or hiring a professional plumber to deal with the situation, here are a few examples of things you shouldn’t put down any drain in your home—even if that’s the easiest way to get rid of it.

Don’t put these things down the drain

Pouring, dumping, or stuffing the following items and materials down any drain in your home is a bad idea:

Grease and oil

Whether it’s grease leftover from cooking, or oil you’ve discovered has gone rancid, do not pour it down the drain. Even if it’s in liquid form when you dump it, it can still cause or contribute to clogs that could wreak havoc on your plumbing.

Kitty litter

This should go without saying, but kitty litter does not go down the drain—even if it’s the flushable kind. Not only can it cause major blockages in your pipes, but it may also contaminate your water supply.

Potting soil

Repotting houseplants or doing other minor indoor gardening tasks in a sink, tub, or shower may be convenient, but if there’s a chance some potting soil could end up going down your drain, find somewhere else to handle it.

First of all, soil is a lot denser than it seems, which means it can easily clog pipes. Also, if some gets stuck down there, it could make your drain smell bad.

Coffee grounds

Although sometimes touted as a way of deodorizing your garbage disposal, coffee grounds really shouldn’t go down any drain. That’s because water makes them clump together, and over time, they can build up and lead to blockages. Use them in your garden instead.