Step 9: Remove the Plastic Retainer
Set the retainer to the side.
You can now try simply dumping the last part out of this section of the cartridge since the retainer is no longer there to keep it. However, if it does not freely fall out, this may be the problem with the cartridge.
Using a flat blade screwdriver, insert the screwdriver into the end where the retainer was and gently twist the inside section to break it loose. Next, using the holes along this unit, help the inside piece to come completely out.