The junk drawer is the MVP of making your home seem meticulously tidy, and it’s also proof that “organized chaos” is a valid method of organization. But you should still be careful about what you toss in there; loose batteries, for example, are a fire hazard.

If metal comes into contact with both the positive and negative posts of a battery, it could cause a short circuit that generates enough heat to start a fire. And chances are pretty good that your junk drawer is currently housing a few metallic materials: paper clips, hardware, coins, keys, tacks, spare chargers, steel wool, pens, and aluminum foil can all pose a threat.

As Reader’s Digest explains, 9-volt batteries are especially unsafe because their positive and negative posts are right next to each other. But even if you’re only storing AA or AAA batteries—or any other batteries where the posts are on opposite ends—it’s probably not worth the risk.

The easiest way to prevent a fire is simply to keep your batteries out of your junk drawer and away from metal objects altogether. If you’re short on space, however, there are a couple other safety measures you can take. The National Fire Protection Association recommends storing batteries in their original packaging, or covering the posts with masking, duct, or electrical tape when you’re not using them [PDF]. You also shouldn’t throw 9-volt batteries in a container with other batteries, since those count as metal objects, too.

Once you’ve fire-proofed your junk drawer, find out how to avoid six other common household fire hazards here.

[h/t Reader’s Digest]