Sweetcocoa is right. The Aubrey's Swimmer shampoo makes an excellent, gentle clarifier. No stripping!
Gigi is right, too. The ACV is good to use as a clarifier. You can adjust proportions accordingly with distilled water to make stronger or weaker in terms of clarification.
I would also mention the Giovanni Tea Tree shampoo. It works well for clarifying and is a good regular shampoo. I use as the latter.
Caress, those Avalon Organic products are supposed to be wonderful. I smelled that lemon verbena in Whole Foods...just lovely.
You might also want to try the clarifier by EO products. I think theirs is lemon verbena too...shampoo and conditioner available.
~Jade~