Here are the steps:
1) Go to the post office with your receipt.
2) Ask the post office person that you want to know whether you money order has been cashed or not.
3) She/He will give you form called 'PS Form 6401'.
4) Fill the form, tell her that you want the scan copy of front and back of your money order, pay the fee.
5) Wait and after 10 or 15 days you will receive a letter from USPS with the front and back of your money order. You will only receive the letter if the money order has been cashed. If not, you will have to wait for it to be cashed.
6) There is no way to check the status of your request online.
I hope it helps.
Yeap I too have the same question? COuld you please tell us?