If you are looking for an inexpensive hair curling strategy, wash your hair with Coca Cola. The cola rinse turn your fine, straight hair into shiny, textured beach curls.
The secret is this: Coca Cola contains phosphoric acid. This means that the solution of Coca Cola has a very low pH level (Coca Cola Classic has a pH of 2.5). As an acidic solution, when applied to the hair, it causes the cuticle of the hair to contract (or tighten) and will make the hair appear smoother and shinier. This also means that the hair (particularly hair prone to curl) will have its natural curl enhanced.
You simply apply the Coca Cola to the hair (it can be flat, since the carbonation isn’t necessary and doesn’t affect the acidity) and allow it to remain for a few minutes (5 to 10 minutes or so) then shampoo the hair. It’s important to shampoo the hair after treating it with the Coca Cola since the beverage contains a lot of sugar and could result in a gummy or crusty residue once it dries otherwise. – hairfinder.com
Watch the video below and see for yourself what happens if you rinse the hair with Coca Cola