There are a number of items you cannot store at 2&17 Storage.
You cannot store combustible materials because of the threat of them catching fire. These items include fireworks, fuel tanks, fertilizer, paint thinner, and so on. If it seems like it'll easily catch fire, avoid storing it. You also cannot store firearms.
You cannot store living animals or plants. Do not treat a storage space as a replacement for a proper pet sitter. Not only are storage spaces not built for people or animals to live in them, but the food you leave out for your pets could also attract pests. Similarly, plant soil could attract pests as well.
You cannot store food of any type including, but not limited to, canned foods, perishable foods, dry foods, or pet food for similar reasons. Food will attract pests and will cause an infestation in your storage space and spread to others.
Lastly, you cannot store illegal items such as prohibited weapons, illicit drugs, drug paraphernalia, and stolen items. If it's not legal to house it elsewhere, you cannot store it here.