Prepping, or preparing, cloth diapers for first use depends mainly on the fabric. The CD 101 post on material and fabrics mentions this (one sentence in the middle of a long post. Hey, I said "mentions".) Most diapers will only need one wash in order to be "prepped". Pocket diapers with fleece inners, microfiber inserts, covers, cotton fitteds, all will be fine with a single wash - unless the manufacturer recommends otherwise.
If the diaper is made of bamboo, hemp, or other natural fiber, you will need to wash (with detergent) and dry the item several times to strip out the natural oils. The actual precise number of washes varies - every time I buy hemp or bamboo prefolds I am given different instructions by the maker. I generally wash three times before first use, knowing full absorbancy will come after about wash 8. In those trial wearings, we are usually at home on a weekend (so a leak can quickly be changed and isn't dire), and I change her frequently so the diaper doesn't get too soaked. With this method, I'm not just washing and washing without using the diapers, but I realize they won't be fully absorbent until after a few of these short trial wearings.
Because of the oils in bamboo and hemp, when doing the first few preparation washes, wash these diapers separately from your other diapers. That way the oils don't coat your other diapers and lessen their absorbency. When I'm prepping diapers, unless I have a huge load, I will often throw them in with towels for the first few washes. It feels less tedious that way, and they are getting detergent and dryer time, which is important in the prepping process. Also, it doesn't feel like it's "holding up" the laundry cycle for "real" laundry that way either.
|Wow, she was leeeeeetle! around 9 months when this photo was taken|
Prefolds arrive at your door brand spanking new. Looking like a crisply pressed white shirt, you may not recognize them as actual prefolds, or think that they will function as absorbent diapers. They will - they just have to be prepped. Again, the actual number of times varies. I also wash/dry these around three times to get them moderately fluffy, and then start the trial wearings. Bleached cotton prefolds will probably be ready for wear in four washes. Organic cotton prefolds may have more of the natural oils left in them, and may need one or two more washes to fluff up well.
|Brand spanking new on left, after one wash in middle, after two washes on right. See how much fluffier - and therefore smaller - they get. After this there wasn't much change in fluff or size.|