Using soapwort or another natural foaming agent that is not based on sodium lauryl sulphate or other harsh unnatural chemicals. Just curious to know what you have used for the 'soap' part of the shampoo.

Castile soap. You can buy it in the bottle and dilute it 1 tbsp to 16 oz water and it lathers good. Find it at any health food store. It's a liquid and has been around since 1800's. You can use it on everything it's so gentle. I've used it and it contains no synthetics at all.

Or goat milk soap bar www.dandesoap.com. She also carries a castor oil shampoo bar.

Everything you buy these days has that mess in it. Also, you can take soap scrapes, place two pieces or one motel sample soap, into a 16 oz jar or bowl. fill with water. It will gel overnight, stir and it's ready to use. Plus you are recycling your left over soap. I've used all three and my hair is down to my waist. I have curly hair and make a rinse out of lavender and water. I don't add any sudsing agents. This rinse still cleans the hair without stripping it of needed oils. Do you have curly hair or straight?

I'm gonna star this because I find it interesting...

EDIT: Straight hair needs more shampoo than curly --the curlier the hair is the more likely somebody could get by with a rinse. Even with straight hair the rise is a good idea every now and then or you can make a bunch and leave it in an old coke bottle and keep it next to the tub. At the end of your shower you can poor it over you hair and it will be cold which will leave your hair extra shiny because the cold water will smooth the hair out (think of how it closes the pores on your face). You can try shaving off an amount of Neutrogena soap for sudsing purposes (the unscented type).