St. Cecelia Vinegar, 1865

The first skin-care receipt in The Handbook for Ladies' Maids:

ST. CECILIA VINEGAR. This vinegar is used for cooling and strengthening the skin. Spirits of wine 10 parts, Strong white vinegar 10 parts, Gum benzoin 10 parts. The gum, powdered, and the spirit are macerated till the former is dissolved, the materials being kept in a close bottle. The vinegar is then added. The employment of a dozen drops of this liquid in half a glass of water will give a healthy tone to the skin which is bathed with it and will be followed by no ill effect. 

---The Handbook for Ladies' Maids, 1865

Equal quantities of benzoin gum, spirits of wine, and white wine vinegar is fairly straightforward. 

Vinegar, spirits of wine, and gum benzoin powder.

Equal quantities of benzoin gum, spirits of wine, and white wine vinegar is fairly straightforward. I used 10 mL of each, and in my first attempt discovered that failure to stopper the bottle will result in the alcohol evaporating. A second start proved more successful. However, this quantity of benzoin doesn't fully dissolve in either liquid. It suspends for a while, but even with time and regular shaking, it still precipitates out.

Finished vinegar and the water ready to use.

Adding 12 drops to 4 oz of water gives clear water with a faint odor of benzoin gum (and fainter vinegar). I didn't notice any particular sensation or effect on my skin. Looking at some of the other receipts, I suspect that this author believes gum benzoin to be a skin-care panacea. I have not found any modern opinions on how benzoin affects the skin: it appears more popular for perfume, incense, and flavoring than as a skin-care remedy.