You may have heard that you can now take duty free liquids on board planes, which means you get to take them home with you, right? Wrong. Many bargain-hunting travelers enjoy stocking up at duty-free shops as they head home. But you may get nailed once you pass customs, especially if you’ve got a connecting flight.

For example, if you buy cologne in Munich, and connect through New York on your way home, you probably won’t be able to get that cologne in your carry-on past security again and onto your connecting flight. So if you do buy duty-free, you must remember to switch any liquids or lighters over to your checked bags once you’ve cleared customs, but before you’ve re-checked your bags for the final leg of your trip.