Hello Kindly don't use charcoal or any other product apart from a good toothpaste and soft bristle tooth brush. The discoloration may be extrinsic because of food debris or calculus (due to improper oral hygiene ) or the tooth discoloration is intrinsic means that is nothing to do with your oral hygiene For Extrinsic discolouration - scaling (normal cleaning of teeth by a dentist ) Intrinsic discolouration -cosmetic treatment(veneers or crowns)

Try Sparkle or Snow Dent toothpaste  Followed by scaling .

Don't use a lot of products first of all And a picture will be helpful to know the exact cause

Various reasons besides smoking can cause yellowish discoloration of teeth. Intrinsic Stains, 1.prolonged  certain specific medications, if any. 2.due to acidity wear off of enamel layer, results in dentinal exposure which appears yellow in colour. 3. genetically enamel layer is thin in nature 5. developmental disturbances in teeth, dark yellowish These do not get corrected even after scaling.but other treatment options are available. Extrinsic stain, 1.certain food such as coffee, tea, termaric, dark berries, red wine,, rough teeth surface retain more than usual stains in teeth.which are sometimes very difficult 2. Accumulation of food debris and improper brushing lead to formation of tartar(yellowish in colour) which may further transform into calculus(whitish, yellowish,grayish,blackish). Scaling can correct them. Edible Soda, may help. But clinical screening is mandetory to find out the exact cause and to elicit the permanent solution with respect to that.

Please don't use things like charcoal powder ...it won't be of any use...adding a picture of ur teeth would have been helpful to know the exact cause....if the reason is calculus deposits scaling is needed...and if any other cause...then aesthetic treatments are required

Whitening of teeth should be done only by dentist. Using over the counter gels and pastes are harmful as the concentrations of the required whitening agents wont be maintained properly( so doesnot work on teeth properly). If you visit dentist after lockdown you can see white teeth in a weeks time rather than trying numerous products for many months