Indulge in relaxing and revitalising facial treatments Cardiff at Skin ‘n’ Tonic. All our facials use leading professional skincare brand MONU from Susan Molyneux. Using only the purest plant extracts and essential oils with no synthetic perfumes and colours, none of which are tested on animals. Leading to optimal results. Facials are the perfect way to deep clean, revitalise, nourish and rejuvenate tired, stressed skin, bringing about healthy, glowing skin.