As we all know shaving brushes is a source of anthrax and other horrible germs. So how do you make sure your thrifty barber only uses his disposable shaving brush once? Apart from making it out of paper, that is? Fear not, Marguerite Faučon secured a an Imperial German Patent on a self destroying disposable shaving brush back in 1909.

The idea is sound enough, for certain values of sound. You wanted to make sure your barber used a clean, hygienic, and preferable antiseptic brush when he lathered you up. but how could you at a glance see that this was the case?

Or, as the translated patent text puts it:

The well-known, for health reasons intended for single use only and soap-soaked shaving brushes have the disadvantage that they are re-usable not necessarily prevent it.

The purpose of the present invention is now to arrange the shaving brush so that it automatically destroyed after a single use or marked in such a way that one immediately sees that it has already been used once

From Imperial German Patent 215703

I suspect the machine translation leaves something to be desired… but in short, Marguerite pointed out that the disposable brushes of the day had the disadvantage of being reusable. Today we would likely see that as an advantage, but we don’t live in fear of being infected with disfiguring diseases at out local barber. Arguable the idea of a self destroying disposable shaving brush is redundant in this day and age.

In order to prevent reuse, Marguerite proposed a brush that would change appearance when used, and fall apart after use.

The know was normal enough. Again, for certain values of normal.. the patent text suggest making it out of cotton thread or other capillary material. The knot area – c on the drawing – would be impregnated with a chemical that would decompose on contact with water and/or soap and discolor the cotton brush.

The chemical suggested is known as phenolphthalein. It is commonly used as a pH- indicator, and as would react well to a soap. Soaps are usually somewhat alkaline, and would turn the compound pink.

In addition to turning the knot pinkish, the reusable handle described in the patent contains one or more blade placed in between springs used to hold the knot. These – marked f on the drawing – would cut the bindings of the knot upon insertion. The brush would keep together as long as the knot was in the handle, but upon removal it would disintegrate into a pink pile.

The last thing shown in the patent is a box for disposing of the knots. Much like using a sharps container for syringes, the knot could easily be inserted into the know, but would be pulled out of the handle when the handle was pulled back.

The cotton knot would stay in this box, and fall apart. And be pink. The chance of reuse would thus be slim to none.

There is no reason why Marguerite’s self destroying disposable shaving brush wouldn’t work as intended. And there is no reason why it wouldn’t be successful back when it was invented. But today? The whole reason d’etre for the invention is no more. The risk of getting anthrax or another disease from a visit to the barber is remote, and modern medicine have made most infections a minor matter.

You can read the machine translated patent over at Google Patents, and the original at Espacenet.