The Everpure filter cartridges have an outer pressure shell that is made from aluminum, which offers the benefits of being both lightweight and able to withstand higher pressures. The outer surface of the aluminum filter cartridges are relatively soft and therefore susceptible to scuffing, scarring and carbon spotting which can occur during the production process, as well as small indentations where the filter cartridges are gripped. These are nothing more than cosmetic blemishes and do not affect the filter cartridge’s performance. There is also a tendency for some residue of the carbon powder (used inside the cartridge) to settle near the top. Just a bit of excess and can be wiped away.