What would be a good way to whiten my teeth in two days with household items?

Unfortunately: The only way to get instant results is by seeing a dentist who does in office whitening. I would not suggest experimenting with household items which could cause serious medical issues. Hope this helps.

Be careful: I would see a qualified cosmetic dentist for approved and safe options for tooth whitening. There are degrees of whitening whether it be surface or deeper but you don't want to damage your tooth. Baking soda will help with surface cleaning but can be abrasive. Be careful with otc hydrogen peroxide, can damage tissue. No complete whitening can be done in two days that doesn't change your tooth.

Can't & Shouldn't !: There is nothing safe to do that! period. Don't even try regardless of who told you whatever or what you read! if you have some special reason for 'instant' whitening, then consult with a local dentist who offers in office tooth whitening. Don't use 'mall' whitening salons either!