- > Appendix C > USPS Packaging Instruction 8C
A corrosive is any liquid or solid that causes visible destruction or irreversible alteration in human skin tissue at the site of contact or a liquid that has a severe corrosion rate on steel.
A Class 8 manufactured article that contains minute amounts of mercury (such as compact fluorescent lamps [CFLs]) that meets the standards below is permitted in domestic mail provided all the applicable requirements in 348.22g are met.
A noncombustible absorbent/cushioning material, capable of containing any leakage in case of breakage, must surround each device.
The device(s), and its absorbent/cushioning material, must be packed in rigid, strong outer packaging.