Lucy, I'm copying & pasting from the NZ Cherub Tree website:
www.cherubtree.co.nz/trouble.html
What is Stripping?
If you notice that your Cherub Tree nappies are starting to smell strongly of ammonia – often obvious as soon as your baby urinates, then it may be time to strip your nappies.
‘Stripping’ simply means washing the nappies in a way that removes excessive build up of washing powder or creams and lotions.
Simply wash the nappies on one cycle up to 60 degrees with NO washing powder. Then, run a second cycle with 1/2 cup of baking soda or white vinegar in the rinse cycle. Rinse again if necessary.
Always dry your nappies in the sun and fresh air where possible.
Help, my nappies are leaking.
The three main reasons for leaks with cloth nappies are:
The inserts are soaking wet and when any pressure is applied (ie your baby sits down) moisture escapes out the legs and back. Solution: Add more inserts.
The nappy is leaking – mainly around the legs, but the inserts are still mostly dry. Solution: Adjust the fit. Make sure the nappy is firm (but not tight) around the legs. Ensure you have set the nappy to the appropriate size setting for your child’s weight/age.
My nappies have never leaked... until now? Solution: This is most likely the cause of a build up of washing powder or nappy creams. Strip them (see our 'What is stripping' F.A.Q.)