Let me get this straight....USPS *gives away packing material* and it is *operating at a loss*.
I think I see the problem here.....
They don't GIVE it away to be used for any other purpose than for USPS mailing. It is a violation of Federal Law to use it for any other purpose.
You are not a US citizen, and probably don't realize the background on our Constitutional & Congressional history of our Postal Service.
The USPS was not created as a money making enterprise. It was created to provide a valuable service, interstate communication, to US citizens. The creation of Post Offices and Postal Roads was what Congress was charged with creating when it was added to the Constitution in Article 1 Section 8. It is the US Congress' responsibility to oversee the USPS. The USPS is mandated to adhere to regulations as set out by the US Congress, but it is here for the purpose of providing a valuable service to its citizens, which it does endeavor to do fairly within the restraints of federal regulation and oversight.
The
real reason the USPS is losing money is because of a law enacted in 2006 by lawmakers that requires that Department to fund future retirement benefits (75 years into the future!) in such a way that no other federal program requires, nor do any private sector companies adhere to either.
In my opinion, it was totally asinine to create such a ridiculous rule for the US post office, but the purpose was clearly to force the USPS to either raise prices exponentially &/or force it to lose money so they (Congress) could make a case for disbanding this service to our citizens in hopes of privatizing it, which in turn would end up removing it from being a citizen-owned enterprise to a for-profit enterprise that could/would decrease services & increase costs, which invariably is what happens when public services are privatized. (My interpretation of the facts as evidenced by legislative attempts & actions over past decades.)
That is what is really going on with the USPS. Some lawmakers want it to fail so they found a way to make that happen with total disregard to what is right or fair or for their actual constituents.
I am not saying this for any political reason, but merely to educate those who don't understand what is going on and why your statement is based on insufficient knowledge of the facts.
The real question remains, can you use it for a mold?
No, not legally. At least not the Priority mail boxes. And not the boxes used for sorting mail or for use by Non-Profit mail. This question has been addressed in the past. Read the statement written on the boxes themselves.
See also:
https://faq.usps.com/s/article/How-do-I-Use-or-Reuse-Boxes-Properly