HOW TO KEEP THEM CLEAN? I’VE FOUND THAT MINE ARE GETTING DIRTY AND YELLOW
Just brush them with the same toothpaste that you use for your teeth, and they should be fine. They are never as perfect as when you first take them out of the wrapper, but it certainly does the job until they are replaced after the two weeks.
You can also use briteclean or other cleanses products available in market to clean them.