Customs Duty from the U.S. Customs Service

The U.S. Customs Service provides these 10 good tips for on its Web site for cruise passengers and others who are entering the United States. Don't rely on friends and shopkeepers for advice on what items "will clear Customs". Instead, obtain this information directly from the U.S. Customs Service.
Declare "duty free items", even if purchased in "duty-free" stores.
Do not attempt to bring unauthorized fruits, meats, and dairy products into the United States without first checking whether they are permitted.
Know the difference between goods for personal use vs. commercial use.
Know the difference between prohibited merchandise (such as ivory, tortoise shell products, absinthe, and counterfeit items) and restricted merchandise.
Be aware that many foreign manufactured items are not FDA-approved and, consequently, cannot be brought into the U.S. Also, when traveling abroad, bring only the amount of medication you'll need during the trip.
Do not attempt to return with Cuban cigars, unless they were purchased in Cuba while on authorized travel.
Know the rules governing the $800 exemption on goods brought back from abroad.
By law, Customs officers have the authority to conduct enforcement examinations without a warrant, ranging from a single luggage examination up to and possibly including a personal search.
Be sure and read U.S. Customs Know Before You Go brochure. You may request a print copy of the brochure by writing to USCS, P.O. Box 7407, Washington, D.C. 20044.