Natural fibers such as unbleached cotton, organic cotton, and hemp contain oils and waxes that can make diapers repel liquid rather than absorbing it. Removing the oil requires some laundry effort, but once the diapers are prepped they will be incredibly absorbent. Remember to prep these types of materials separate from your regular diaper laundry, or oils you are trying to remove may re-deposit on other diapers in your collection.
|Unbleached cotton prefold after removing natural oils. A new cotton prefold will be stiff and repel liquid, but after prepping the fabric will shrink and "quilt" as it becomes soft and absorbent.|
Prepping Diapers for first use
Covers and Microfiber/Minky inserts: Diapers should be washed with detergent before use to remove any residue from shipping. Wash on hot with detergent, and follow with an additional rinse to remove residual detergent. Check the packaging of the diaper for additional instructions. These fabrics do not contain natural oils, and they will not become more absorbent with subsequent washes.
Unbleached cotton: Unbleached cotton prefolds require a lot of prepping. Wash the diapers on hot without detergent 8-10 times (although some suggest 4-6 times is sufficient). You should dry the diapers between washes, although they don't need to be completely dry before the next wash. Drying the prefolds in a dryer helps to remove excessive lint, shrinks the diaper to the final size, and quilts the diaper.
Organic cotton, cotton, hemp, bamboo: Wash the diapers on hot 3-4 times without detergent. If you are prepping prefolds, dry them between each wash to help them quilt. You can find before and after pictures of prepping organic cotton prefolds here.
Prepping diapers made from natural fibers is important, and diapers will become more absorbent as you continue to use them. For example, organic cotton diapers can be prepped for first use in three washes, but they will reach their maximum absorbency after about eight washes.