Valuables clear security without limit inside the US, and that is the easy part. The harder rules are about declaring: carrying more than 10,000 US dollars in cash or monetary instruments across the border must be reported to customs, and many countries set lower thresholds on the way in. Gold, jewelry and watches are unlimited but should be documented for the return trip.None of it belongs in a checked bag. Airlines exclude cash, jewelry, electronics and documents from their liability for lost luggage, so a checked valuable that vanishes is simply gone. Each item page below gives the security verdict and the declaration rule that applies.