12 Items You Should Never Keep in a Storage Unit, According to Experts

Food and Pantry Items

Canned goods, dry staples such as rice and pasta, flour and baking supplies, snack foods, and even sealed pet food are best kept at home. "While self-storage facilities are usually clean and professionally maintained, they aren’t designed to function as pantries," says Maria Gatea, home trends research lead at StorageCafe, a nationwide storage marketplace. "Once any type of food is present—even if it’s boxed or bagged—it can attract pests, which puts everything in your unit and the nearby units at risk."

If your pantry shelves are feeling crowded, Gatea recommends shifting your strategy rather than your groceries. "Store the items you only reach for once in a while, such as holiday serving platters, specialty bakeware, extra sets of dishes, or that oversized stockpot that makes an appearance during big family gatherings. Moving those pieces into storage frees up valuable space in your pantry for the everyday essentials you rely on regularly."

Personal Documents

Important personal documents are better stored at home. "Depending on the situation, a temperature-controlled unit might be OK," says David Hurless, director of operations with Stor-it. "However, consider if something were to happen to the building itself—or perhaps some kind of pest that eats away at paper—it could be such a headache to have to replace. I suggest some kind of protective safe for any important documents."

Damp Items

Most people are aware that storing flammable materials isn’t permitted, but few realize that even slightly damp items, like clothing or sporting goods, can also pose problems.

"When you close up a storage unit and trap the air inside, it creates the perfect environment for mold and mildew to grow," warns Dave Collins, general manager with Sparefoot. "This growth will not only ruin your stored property, but it may also travel to other adjacent units, causing even greater cleanup costs."

To avoid these issues, Collins recommends ensuring that all items are completely dry before placing them in storage. "Use breathable storage bags or covers as opposed to plastic wraps that trap humidity," he adds.

Fur and Leather Goods

Long-term storage of delicate materials such as fur coats and leather furniture often requires special storage. "Over time, natural fibers can dry out and deteriorate if the humidity levels aren't tightly controlled," Collins says. "For long-term preservation, it is recommended that you seek the services of a professional fur-storage company."

Sentimental Keepsakes

Never store family heirlooms, sentimental keepsakes, or anything that deteriorates with fluctuating temperatures and humidity. "Photos, precious art, books, and fabric may all be affected by changing temperatures and humidity," says Kate Ginsberg, founder and CEO of Queen of To Do. "Books can mildew, yellow, and retain odors, photos may discolor and even stick to each other, and fabric will suck up odors and mildew. A lot of this damage isn't reversible." Instead, choose airtight and watertight bins for these keepsakes.

Scented Items

Avoid storing scented candles and strong-smelling products in your storage unit. "These types of products can attract rodents and insects, and can also easily transfer their smells to your other stored belongings," says Collins. "Consider keeping strongly scented items such as candles in sealed containers at your home, where you have full control over the environment of your storage."

Anything Unsorted

Many people cram bags and boxes of random items into storage, intending to sort them later. "The reality is that later never comes around, and it's always pushed to another day," says Linda Chu, professional organizer at Out of Chaos. "Instead, it's best to open bags and boxes to see what is inside and curate the items you truly want to store."

Most important is to cluster like with like and place clear labels on what is inside each box or bag. "Section your storage space into zones so that similar categories are kept together for ease of access," Chu adds.

Batteries

A large number of batteries—particularly lithium-ion—are a fire hazard if left in high-temperature environments or if they break down over time. "Once a lithium battery ignites, it burns very hot and is difficult to extinguish—which is why storage facilities take great precautions to avoid these fires," explains Collins.

Small household batteries are acceptable. However, storing large amounts of batteries can pose safety risks and is discouraged. "Store your small quantity of household batteries in a cooler storage area, and recycle any excess batteries," says Collins.

Future Hobbies

We all have the best of intentions when starting a new hobby. "But if space is limited, and you have not started that painting or knitting project, donate the supplies and make room to store other items," Chu suggests. "The reality is, these supplies have been taking up space in your home. Hiding them in a storage unit will only risk you forgetting it’s there."

Unregistered Vehicles

Even if your storage unit allows you to store a vehicle, you are generally not allowed to store an unregistered or undocumented vehicle. "In addition to the registration requirements, vehicles can leak fluids and present environmental risks to the surrounding areas," Collins warns. "If your vehicle is not operational or registered properly, it is best to store it in a designated vehicle storage facility that has the proper equipment and expertise to safely handle it."

Wine

A standard storage unit won’t provide the consistency fine bottles of wine need, but specialized wine storage spaces can, says Gatea. "These units maintain steady, cellar-like conditions so your collection can age properly," she says. "If you’ve run out of rack space at home, it’s a far better solution than tucking bottles next to patio cushions."

Tires

Many people believe they can store spare tires in a storage unit, but loose tires can be hazardous to other tenants because of the risk of fire. "Tire fires are extremely hot and difficult to suppress," says Collins. "Therefore, many facilities do not permit loose tires unless they are mounted on a vehicle." If you must store seasonal tires, keep them in your garage to protect them from the sun, or hire a specialized tire storage program.