information från Thirsties hemsida:

Double up with natural absorbency.

• Use Organic Cotton Doublers with your current cloth diapering system as extra absorbency for heavy wetters or nighttime      use.
• Organic Cotton Doublers consist of 4 soft layers of 100% GOTS certified organic cotton

Material

• 4 soft layers of 100% GOTS certified organic cotton
• 1 layer 100% polyester

Before Use: Wash 1-3 times using a cloth diaper safe or additive-free detergent.

At Every Wash Cycle:

• Prewash on warm
• Wash on hot
• Add another rinse on warm.
• Hang dry or dry in the dryer on low. If the diapers or pads are stiff after line drying, you can throw them in the dryer on low heat with some wool dryer balls to soften them.

Important Notes:

Use enough water to soak and cover the diapering items and allow them to agitate.
 
Please Avoid the Following:

• Sanitize or Whites cycles on HE machines
• Pure Soap
• Routine use of bleach
• Fabric softener or dryer sheets

These practices and/or additives can void the warranty on your Thirsties products.

*A 15 minute cycle on hot in the dryer once a month is beneficial to lamination, and will not void your warranty.