USPS customs?

I'm not sure if I understand.... But if you mean do you have to have a customs form when you send things FROM St. John, the answer is yes. Any package over 9ozs will require a customs form attached to the outside with the exception of Express Mail. The form is different for Parcel Post and Priority Mail services.

It has been my experience that you can be very vague on the forms, and sometimes on the Priority Mail, you can leave it almost blank, as long as you sign it. It has also been my experience that the packages get "flagged" based on the cost of the postage (ie, highly insured packages tend to get opened up at the Customs office in PR). Duties will be assessed accordingly by the Customs department. Anything purchased here and mailed to the states over $2,000 will require a broker to get released if Customs picks it up.

"Used stuff", I am guess you mean you didn't buy it here or it's not a new purchase??? In that case, you still have to fill out the form, but you can indicate that it's personal items. You shouldn't have to pay any duties on that kind of stuff.

We have to do all of this because we are a duty free port. Just like you have to clear Customs when you leave the VI, anything mailed out also has to clear Customs.

The Virgin Islands charge 6% duty for any products not made in the USA or Denmark. An example could be watches or jewelry shipped to a store for retail sales. If you brought a car made in Japan, you pay the difference on US vs. VI duty and excise tax. USPS is doing the right thing.