Hi, So I have this dental retainer that I was given after my braces came off. It has a pink flesh-like part that covers my upper mouth and then the steel bar is attached to the pink piece to wrap around my front teeth. Thing is I've had this retainer for a while, and when I'm not wearing it I would leave it in water (should I be doing that?) inside a cup. It seems that the color of the pink part is coming off (residue in the cup), and I'm just wondering if that color chemical stuff could be bad for me when I wear it? Thanks.