Reminder ⚠️ Mercury is always prohibited in the mail. This includes antique items such as thermometers, barometers, blood pressure monitors, switches and relays. Mailing mercury isn’t just dangerous. It causes damage and delays for the whole mail system.
ALT The image shows two side-by-side photos of an orange and white kitten with wide, startled eyes, captioned: "When we have to close the Post Office™ because someone shipped mercury."