First of all, a little chemistry. Aspirin is acidic, adding it to the traditional baking soda wash creates a chemical reaction (more than likely, totally harmless but I thought it was counter-productive.) To avoid this, I mixed it in my white vinegar pre-wash rinse. Instructions as follows!
You will need:
Bath full of water
1. Crunch up 2 tablets of aspirin. Since I work with a lot of herbs, I actually have a mortar and pestle but you can also use a spoon or knife to crunch it up. Just make sure you get a fine
2. In your large cup/bottle, mix the aspirin with 1c of water and 1c of white vinegar. Make sure there are no aspirin clumps.
3. Pour over your head making sure to massage liberally into your scalp. I tend to section off my hair and break up clumps of flakes by massaging sore spots on my scalp.
4. Marinate for a about 3-5 minutes.
5. Rinse well with fresh water (not from tub because the white vinegar will actually clean the soap scum off your tub and you don't want that in your hair.)
Overall, I've had really positive results. My scalp seems cleaner and stays clear longer than it did with just the vinegar pre-wash. I haven't even gotten sweaty scalp itchies yet except when I did a control week when I didn't use the aspirin. I'm not sure if adding in aspirin keeps the whole thing "no poo", but I'm not a stickler. I got into it because it made my scalp happy, so I come from that prospective.
Let me know if this works for you! :)