If you want more natural options for whitening your teeth than the ones sold in stores or used by dentists then you can easily whiten your teeth at home as well if you happen to have activated charcoal, lemon and soda.
The simplest remedy is to use just activated charcoal for whitening your teeth. All you need is either tablets or capsules of activated charcoal. If using tablets then you can just rub the tablets onto your teeth until they dissolve and then keep on rubbing your teeth with either your finger or toothbrush. If you have capsules of activated charcoal then open one capsule and pour the charcoal powder onto your toothbrush and start brushing your teeth. No need to worry about the color either as it will all come off while rinsing your mouth leaving you with whiter teeth.
The other remedy for teeth whitening is made by mixing about 1 or 2 teaspoons of baking soda with fresh lemon juice.
When mixing the two then you should end up with something that resembles toothpaste
Now add some paste to your toothbrush and rub your teeth for about 5 minutes. You can add more paste to your toothbrush while brushing to use up all the paste. This mixture will leave your gums tingling a bit (or a lot, depending how sensitive you are) but don’t give up before at least 5 minutes of brushing. The tingling will pass soon after you have finished brushing and rinsed your mouth.
I would stick with the charcoal as the acid in the lemon combined with brushing can damage the enamel. It is even recommended that you wait 20-30 minutes after eating anything acidic to brush your teeth.
True, lemon juice just like baking soda has also some damaging effect on the enamel but when done not too frequently then the enamel should have time to repair itself : )