what is a cheap way to whiten my teeth (other than the strips)?

i have to whiten my teeth before prom, but i was wondering if there were any at home ways to do it, but not the strips
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Lemon juice, baking soda or baking powder can also be used for teeth whitening. Strawberries are natural teeth whiteners, simply rub them directly on your teeth or mash into a paste and apply. Apple cider vinegar can also be used for teeth whitening. More remedies and information regarding your teeth at http://useinfo-teethwhitening.blogspot.c…
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