Fleece liners have two roles. They can be used purely to catch solids and instead of paper liners are reusable. Just hold the soiled liner under the flush (hold tight) and then chuck in with the dirty nappy and wash together. Or they can be used as a stay dry liner for any nappies with organic material, bamboo and cotton will be very wet next to your baby's bottom and although this will not cause nappy rash some parents like to think their baby is feeling dry. They are great for night time use as generally babies do not poo when asleep and most parents find that a good night time nappy will be made from bamboo or organic cotton or a mix. I am a big fan of fleece liners.