Use these guidelines when you’re organizing and cleaning out your space.

1. Paint

It’s hard to regulate the climate in a garage, and the extreme hot and cold temperatures can ruin both unopened and opened paint cans—even if they’re sealed properly. Instead, place paint cans in a cool spot, but away from freezing temperatures (especially latex paints since they are water-based). Store open cans upside down to create a tight seal around the lid.

2. Seasonal Clothing

“Wool jackets, boots, rain slickers, scarves—basically anything you want to bring out of storage and wear when the weather turns—should be stored in an airtight containers indoors,” says organizing and storing expert Emma Gordon of Clutter.com. “If stored in a garage, fumes and superfine dust brought in by the family care will work its way into the containers, making your clothing stink.”

3. Books

Unless your garage isn’t subject to high temperatures, and is well-ventilated, pest-free, and humidity-free, you’ll want to store your books somewhere else. This also goes for magazines, photo albums, and other paper goods. “Changes in humidity will make paper fibers swell and contract, resulting in wildly curled pages and warped spines,” Gordon says. “If it’s a garage in a humid climate, you’ll get mold speckles as well. Books are much more susceptible to pests like silverfish, spiders, and rodents when left in a garage, so it’s best to keep them stored upright indoors.”

Much like books, magazines, and photos, cardboard boxes will also become less sturdy over time because of humidity. Instead, keep anything you are storing in the garage in waterproof plastic containers, which will seal tighter and last longer.

4. Propane Tanks

You can store your gas grill in the garage in colder months, but you’ll want to disconnect and leave the propane tank outside. A leak in the tank can cause an explosion—and fire code recommends that you keep it at least five feet from your house.

5. Wood Furniture

“Throwing a drop-cloth over your wood furniture is not enough to keep it in good condition while storing in the garage,” Gordon says. “Wood furniture is more fragile than it appears because it is highly susceptible to changes in humidity. Just like paper goods, the wood fibers swell and contract depending on the moisture in the air. Over time this leads to cracks that are difficult, and sometimes impossible, to repair.”

6. Food

This will only attract rodents and other pests. This advice isn’t just for dry goods in bags or boxes, but also for canned goods. According to the United States Department of Agriculture’s Food Safety and Inspection Service, high temperatures will put the cans at risk for spoiling. On the other hand, a freezing or damp garage can also be harmful to food. Store foods in a cool, dry place so they won’t spoil faster than usual.

7. Mattresses

Yes, that advice stands even if they are wrapped carefully. “Think twice about storing extra mattresses in the garage: exhaust fumes and superfine dust brought in by the car can settle into the mattress fibers, making for a grimy night’s sleep when you bring it back indoors,” Gordon says. “Besides, there are pests lurking in a garage that you do not want getting in your mattress.”