Use sturdy boxes that stack well. They're generally better than plastic bags, which can trap humidity and cause mildew damage. Use specialty boxes for items such as artwork, mirrors, electronics, lamps, dishes and glassware, mattresses, sporting goods, and musical equipment.
Preventing Damage
Be sure to fill your boxes to the full capacity. Half-full boxes can collapse or damage items while in transport. Be sure to distribute weight evenly in boxes and make sure they're not too heavy. Stack heavier items on the bottom and more fragile items on top to prevent damage. Pack books flat to prevent spine damage.