Dell 5210n Mono Laser Printer User Manual page 34

3. Pull the print cartridge up and out of the printer.
CAUTION: When replacing a toner cartridge, do not leave the new cartridge exposed to direct light for an extended period of time. Extended light
exposure can cause print quality problems.
4. Unpack the new toner cartridge. Remove and discard the print cartridge's protective foam, red plastic strap, and tape.
5. Thoroughly shake the cartridge side-to-side and front-to-back several times to distribute toner evenly.
6. Insert the print cartridge into the printer.