Think about it: When you're on vacation, you drag your suitcase through dirty parking lots, mud, poop and all kinds of gross things. Then when you get home, you unpack and put it away. It's time to get in the habit of cleaning your suitcase every time you get home. All of that dirt, grime and oil can break down the materials that make up your suitcase. But the worst potential threat is mold. When you place your dirty suitcase under the bed or in a dark closet, it creates a breeding ground for mold. To keep your suitcase clean, simply vacuum it inside and out, and use a damp microfiber towel to wipe the rest down.