Obtain the appropriate refill cartridge. Check the model of your Sharpie, and purchase the Sharpie refill cartridge. Cartridges can be bought in most large stationary stores or online from the Sharpie website.
Unscrew the ink cartridge by grasping firmly and twisting in one direction.
Gently remove the spent cartridge. Remove the refill from any packaging and insert into the pen.
Screw the lid on tightly; begin writing.