I usually stick to baking soda and ACV rinses for clarifying, but... You could try diluting the sulfate poo with water. I read on IAGirl's science-y hair blog you can do this with 1-2 teaspoons shampoo in 1 cup water.
CG since 11/2011
2c /3a F /Mii, low porosity

Go To Products /Routine:
Clarifying: Suave Essentials Strawberry
Low Poo: Renpure Luxurious Argan Oil
CO: Suave Essentials Strawberry, V05 Kiwi Lime
RO /LI: Tresemme Perfectly (un)Done, Cure Care, V05 Kiwi Lime Squeeze, Suave Essentials Strawberry, Renpure Brazilian Keratin (old formula)
Stylers: LALSG, AIF, HETT, Suave Professionals Firm Control
PT: IAGirl's as needed