Originally Posted by KetchupNinja
Make sure you are pushing them in while you twist.
The pads are mounted on a plastic ring, which attaches to the cup via 4 little tabs that slide into corresponding slots. To remove, you need to rotate this ring so the tabs are released from their slots.
You have to apply a lot of pressure 'through' the pad, towards the back of the cup and then rotate, to ensure you are actually rotating the ring and not just the pad.