Traveling Abroad and wanting to Mail Hygiene and Bath Items Ahead of time Internationally Need HELP!?

as a ebay powerseller, I ship all over the world its cheapest to mail these usps flat rate priority if the weight is under 4 pounds you can mail first cl but Usa to japan takes a LONG time so ship flat rate its cheaper and quicker and you have tracking or you can take it in your suitcase just not your carry on and avoid shipping all together