Yes you were right you can use peroxide and baking soda, separate and also together
Hydrogen peroxide is a very strong and potent natural bleach and disinfectant. For dental care you should use the hydrogen peroxide 3% variety, which is diluted enough to use on skin or to rinse teeth
When you use it as a natural teeth whitening agent the fizzing action will kill bacteria and seriously clean your teeth
The most common way to use it is to swish some hydrogen peroxide around in your mouth and around your teeth for 1 minute. Then spit it out, do NOT swallow it!!!
Afterward you might notice that your gums are a bit irritated and it can cause teeth sensitivity over time, but it is completely safe. Then brush your teeth as normal. When you use this method only do it maximum twice a day
Baking soda dissolves easily, and is a mild abrasive so it can remove stains. It has anti acid properties so it will protect your enamel from acid attacks. It is anti bacterial which protects you from plaque. And it has anti fungal properties, all which makes it very useful as a dental cleaner
You could use baking soda by itself, by putting some baking soda on your toothbrush and gently brush your teeth with it, don't overdo it. Be careful the baking soda might irritate your gums
Another long trusted and very powerful natural teeth whitening treatment is to mix baking soda with salt and brush your teeth with this
A third option is to mix half a tablespoon of baking soda with half a teaspoon of vinegar, add a pinch of salt and brush your teeth with this
Be careful, don't use these methods too much, although they are very effective it is not always necessary to use this kind of force to clean your teeth
To use hydrogen peroxide and baking soda together, mix 1 teaspoon of baking soda and add hydrogen peroxide until it has the same consistency as a toothpaste. Brush your teeth with this and after that brush with your normal toothpaste. To finish it off, you can swish some peroxide around your teeth and after that rinse with clean water
Hopefully this will be of any help, good luck.
For more info on natural teeth whitening: http://www.natural-homeremedies-for-life.com/home-remedies-for-whitening-teeth.html