Always secure and lock your cargo using a padlock/tote-ties.
No, weapons (guns, ammunition, artillery), or contraband items are not allowed to be shipped with your cargo.
Liquids/fluids should be packed in hard body plastic tote containers.
If shipping books, use multiple small boxes (e.g., 12x12x18) instead of larger boxes. Books tend to be heavy and are handled well as small compact boxes.
For furniture, dressers, and mattresses, always invest in wrapping your cargo with shipping blankets to protect the edges. Thereafter, wrap the items with shrink wrap on top of the blankets.