To learn more about what products you should avoid using, click here. Step 1: Brush your extensions. ... Step 2: Prepare your sink. ... Step 3: Shampoo each weft. ... Step 4: Condition each weft. ... Step 5: Apply a deep conditioner or hair mask. ... Step 6: Rinse out each weft. ... Step 7: Lay each weft out to air dry. ... Step 8: Comb each weft.