The Ancient Romans believed in using urine with goat milk to make their teeth look whiter. Pearly white teeth symbolized beauty and marked wealth. In the Auyrveda medicine system, oil pulling was used as an oral therapy. For this process today, swish coconut or olive oil in your mouth for up to 20 minutes each day. In the late 17th century, many people reached out to barbers, who used a file to file down the teeth before applying an acid that would, in fact, whiten the teeth. Although the procedure was successful, the teeth would become completely eroded and more prone to becoming decayed. Guy de Chauliac suggested the following to whiten the teeth: "Clean the teeth gently with a mixture of honey and burnt salt to which some vinegar has been added." In 1877, oxalic acid was proposed for whitening, followed by calcium hypochlorite.