How to Replace a Grohe Cartridge | eHow 00:30 Step 2 Use a hex key on the star-shaped aperture located under the spigot or faucet handle. Turn the hex key counterclockwise four to six complete rotations. This will loosen the spigot and handle enough that it may be removed. Step 3 Remove the spigot and handle from the faucet assembly to reveal the cartridge system. Step 4