Citric acid

This acid is what is found in citrus fruits. It is a relatively gentle acid but can be an irritant. It is used in a variety of skin care products and can be included in AHA’s (alpha hydroxy acids which are plant based acids)  Some have used the juice of lemons to whiten nail plates. This can work due to the acidity but it is not ideal to soak the nail plate for too long in a water based chemical.