mummytummy - I've only recently started to not use detergent, and my ittis started shreading about a month or so ago, so nope, not that. I think it's weird that it's only itti bittis that are doing it.

limeslice - my nappy setting on my washing machine has a rinse cycle before doing a regular (but gentle cycle). I always hang my nappies in the sun as well. And all the soiled nappies are thoroughly rinsed.