Elder Flower Water (Aqua Sambuci) is an official preparation of the British Pharmacopoeia, which directs that it be made from 100 parts of Elder Flowers distilled with 500 parts of water (about 10 lb. to the gallon), and that if fresh Elder flowers are not obtainable, an equivalent quantity of the flowers preserved with common salt be used. The product has at first a distinctly unpleasant odor, but gradually acquires an agreeably aromatic odor, and it is preferable not to use it until this change has taken place.

Elder Flower Water is employed in mixing medicines and chiefly as a vehicle for eye and skin lotions. It is mildly astringent and a gentle stimulant. It is the Eau de Sureau of the Continent, Sureau being the French name of the Elder.

Elderflower Water in our great-grandmothers’ days was a household word for clearing the complexion of freckles and sunburn, and keeping it in a good condition. Every lady’s toilet table possessed a bottle of the liquid, and she relied on this to keep her skin fair and white and free from blemishes, and it has not lost its reputation. Its use after sea-bathing has been recommended, and if any eruption should appear on the face as the effect of salt water, it is a good plan to use a mixture composed of Elder Flower Water with glycerine and borax, and apply it night and morning.

Here is a recipe that can be carried out at home:

Fill a large jar with Elder blossoms, pressing them down, the stalks of course having been removed previously. Pour on them 2 quarts of boiling water and when slightly cooled, add 1 1/2 OZ. of rectified spirits. Cover with a folded cloth, and stand the jar in a warm place for some hours. Then allow it to get quite cold and strain through muslin. Put into bottles and cork securely.

From: A Modern Herbal