I see a lot of questions on some of the Facebook cloth diapering pages I am on about prepping new diapers, so since I just got a new batch of diapers for Christmas and thought I would go over how I prep new diapers. I got 3 Grovia all in ones, 7 Bumgenius 4.0 pocket diapers, and 1 Bumgenius Elemental (the new style.)
The first thing I did was wash my purple Bumgenius separately from the inserts or other diapers. In my past experience the purple (Dazzle) color of bumgenius tends to tint the microfiber inserts and white PUL on other diapers a pinkish/purpleish color. I washed the purple diapers on hot with my detergent one time. Microfiber really doesn't need to be prepped at all, I just wash to remove anything that could be on there from manufacture/shipping.
Then I washed the rest of the diapers all together on hot with detergent. I dried the other pocket diapers, and then put the all in ones back in the wash to go through another wash cycle. The all in ones I have are made from cotton, and cotton needs to be washed a few times on hot to remove the natural oils and to reach its maximum absorbancy. This would apply to prefolds, flats, and hemp. I only washed mine twice because I was excited to get them on her, but I just knew I may have to change them more often since they wouldn't be at the max performance yet. I dried them in the dryer on medium to allow for any shrinking of the cotton that may occur. (None that I noticed) I did notice that the BG elemental dried really fast! I think I am really going to like that diaper.
There you have it! It isn't rocket science, pretty simple if you ask me!