I have used the toothpaste and powder together for more than a month. It does work to remove the yellowish slowly overtime. You don't immediate result however charcoal is not as harsh as those whitening product. Will continue to use.
Using it on 10 Apr 2020!!!
I am having this stain for quite long almost 3 years as I am a ex-Smoker.
However, after using it , it helps to remove little by little as using it daily as notice by my family.
It works, but required sometime to remove it entirely.