Sending pins to Japan

I agreed to a trade with a person in Japan and I was wondering if anyone on the forum has experience with sending packages to Japan. Would it be better to send a padded envelope or a small box? Is there a difference in the cost between the packages? About how long does it take to get there, and can the package be tracked? The pins are not very expensive, mostly rack pins, so I am not worried about insurance, but what do I do about the customs form? Any help would be appreciated. Thanks.

I have sent there before and used a bubble envelope.

How many pins are you sending?

If you don't have a stamps.com account (or other discount postage provider), sign up for free with USPS.COM and you can use their "Click 'n Ship" option. It might save some money for smaller weights, but eventually the price evens out for higher weights. You can complete the Customs declaration online and then your label will print out with a tracking number (which is supposed to be trackable after it leaves the US, but it all depends on the destination post office.)