To mail an envelope through USPS, follow these steps:

1. Fill Out the Address: Write the recipient's address and your return address on the envelope as usual. CRE's address is 77 Massachusetts Ave, Rm 9-314, Cambridge, MA 02139.

2. Cost Object: Write the cost object in the upper-right corner, where the stamp typically goes. Mail Services will apply the necessary postage and bill the cost object accordingly.

3. Locate a Mail Bin: Find the nearest mail bin. The closest one to CRE is on the 1st floor of Building 9, near the rear (east) entrance. If you are coming from the third floor, exit the elevators on the first floor and turn left. The mail bin will be on your right.
   

4. Place the Envelope in a Mail Bin: Once your envelope is filled out, place it in the mail bin.

Additional Information

• List of campus mailbox locations
• MIT Mail Services Home Page