Increasing numbers of travelers are shipping bags instead of checking them. But there are some things you shouldn’t ever ship, even if it may still be legal to do so. Since only a handful of shipments are inspected, many potentially dangerous items make it onto planes. And they’re not just items which common sense tells you shouldn’t be shipped, like fireworks or flammable liquids.

You should also avoid shipping laptops, digital cameras, or anything with a lithium-ion battery. These batteries can spontaneously combust and have been suspected of causing fires on board cargo planes. Amazingly, most lithium batteries are still perfectly legal to ship. Most aerosols and some paints are also combustible, and while restrictions on shipping these items vary, they should not be shipped in regular cargo, either. Remember, it is possible to ship these items safely, as long as you inform your shippers and follow their hazardous materials procedures — don’t try sneaking them in.