Use iDye Colour Remover - .49 oz/14 g to remove or lighten colours and brighten whites, Comes in an EASY-to-use soluble packet for use with all kinds of fabrics. Does not contain bleach. One packet treats 2-3 lbs/1-1.3 kg of fabric.

• Conforms to ASTM D 4236.
• Made in the USA.
• Product Dimensions: 8.6 x 0.4 x 14 cm

Instructions

1. Fill a stainless steel, aluminum, or enamel pot with just enough water for the fabric to move freely. Turn on medium to high heat.
2. Add the iDye Color Remover soluble packet to water and stir.
3. Add garments and raise the temperature. For cotton and silk: bring the temperature to just below a simmer. For polyester: bring to just a rolling boil.
4. Maintain temperature and frequently stir for 10 to 20 minutes or until the colour has left as desired.
5. Wash the garment with a mild detergent and dry it.

Colour Remover Instructions (detailed) here

CAUTION! Harmful if swallowed. Contains Thiourea dioxide. Give water or milk if ingested, and call a physician. Avoid contact with eyes. Keep out of reach of children.