Baking soda on its own can be used to whiten teeth, obviously not to frequently and for long period of times, but try to use it morning and night after brushing your teeth with colgate or whatever and see if it helps
There are a lot of good answers to you question, if you try some of those, and want a better way to do that. Go to your dentist and ask them to make you a mouth piece that you use for a few days, than when your teeth get a little dull you just do it again and poof they are back to white again. These mouth pieces are a little costly but you will have them for ever. Try to stay away from a lot of red wine, and coffee, that also takes away the white in your teeth.
Do not be putting salt/bakin soda on your teeth a it just takes a layer of, teeth whitening tooth pastes honestly don't work, don't bother just get the paste with the most fluoride in it, brush your teeth three times a day!
Crest and colgate works alright. Here are some tips on your journey to whitening your teeth. Eat a lot of cruchy fruits such as appeals strawberries are very good for your teeth even tho it's not crunchy.
Sugar free gum is good for you. Stay away from soda and spicy food. Drink some warm water before you go to sleep.
Do Not use baking power or lemon or any type of homemade products they whiten your teeth but they have very bad side effects.
Colgate Optic (red tube) is absolutely the best! Dr. Oz even recommended it :) . I bought some for my daughter and by her next visit it was so noticeable. I use it along with baking soda or peroxide for a quicker "fix". Keep on smiling ;) !
Try Idol White. These pens seem to be doing a great job of whitening my teeth. I drink a lot of coffee and it is definitely making a difference and for such a good price - a no-brainer. I can't believe what a good job they've done and I've had no issues with tooth sensitivity. Click below for more info. http://tvoffersproducts.com/IdolWhite
honestly colgate optic white hasn't made a noticable difference on my teeth but my mom has really white teeth and shes really good abt brushing her teeth but she brushes them with toothpaste and baking soda on her toothbrush and then after rinses her mouth with a cup filled 3/4ths with water and 1/4th hydrogen peroxide. it works really well for her! im trying it today and im going to see how well it works for me