Arnica Hair Wash
When the hair is falling off and becoming thin, from the too frequent use of castor, Macassar oils, &c., or when premature baldness arises from illness, the arnica hair wash will be found of great service in arresting the mischief. It is thus prepared: take elder water, half a pint; sherry wine, half a pint; tincture of arnica, half an ounce; alcoholic ammonia, 1 drachm — if this last named ingredient is old, and has lost its strength, then two drachms instead of one may be employed. The whole of these are to be mixed in a lotion bottle, and applied every night to the head with a sponge. Wash the head with warm water twice a week. Soft brushes only must be used during the growth of the young hair.
Source: Our Knowledge Box, ed. G. Blackie
Hair Wash
One penny worth of borax, half a pint of olive oil, one pint of boiling water. Pour the boiling water over the borax and oil; let it cool; then put the mixture into a bottle. Shake it before using, and apply it with a flannel. Camphor and borax, dissolved in boiling water and left to cool, make a very good wash for the hair; as also does rosemary water mixed with a little borax. After using any of these washes, when the hair becomes thoroughly dry, a little pomatum or oil should be rubbed in to make it smooth and glossy — that is, if one prefers oil on the hair.
Source: The Canadian Family Cookbook, Grace E. Denison