Some use strong scented herbs - rosemary, rosepetals, lavender, etc., (some crush some don't). Heat up the vinegar (I use white vinegar as well as KT) to just before boiling so the heat from the vinegar will help it diffuse.
Some use white vinegar instead tho' for brunettes ACV is probably best.
You can try using Japanese rice vinegar.
Thanks Fox:
If you are using dried herbs, you don't need to crush them. If you are using fresh herbs, then crushing will help to break the cell wall and release all the good things inside.
I used herbs in my vinegar rinses quite awhile, but I have found it is much more easy to use essential oils. Peppermint is one that really effects the scent of your mixture. Be sure to shake well before pouring out any of your vinegar rinse to dilute or you'll get all your EO's at once!
I add the following to my litre bottle of vinegar mix: I use about 10-15 drops each.
Tea Tree
Lavender
Clary Sage
Peppermint
Cedarwood
Rosemary
Peppermint
You will find the scent to be totally different.
I think that Peppermint helps to stimulate blood flow in the scalp, so that's always a good thing.
I also saved this info from:
http://www.kevala.co.uk/aromatherapy/peppermint.cfm
Peppermint has a long tradition of medicinal use. In 1879 the British Medical Journal reported the reliving influence of menthol upon headaches and neuralgia.
Peppermint Oil is both soothing and energising. The distinctive 'coolness' of the oil stimulates the body and mind.
Peppermint invigorates, revitalizes, refreshes and also brings mental clarity. Blending well with other essential oils peppermint creates excellent blends for massage. Used in a cool bath Peppermint is an ideal energiser, yet a soothing bath of peppermint will help you unwind and relax at the end of the day.
I also had this, but not the webaddress saved:
http://www.kevala.co.uk/aromatherapy/peppermint.cfm
Peppermint has been used in Eastern and Western medicine for a variety of complaints, including indigestion, nausea, sore throat, headaches, toothaches and more. Should not be used during pregnancy.
Hope that helps! Do DILUTE! It will help soooo much! By the way, that rice vinegar makes a wonderful Chinese Cabbage Salad! It is less potent of a smell and is sweet, so it might also add a moisture to the hair like honey does.