We have for some time 2 Sigg bottles which have super survived despite regular cleaning in the dishwasher and filling with apple juice (exemptions from some scratches). Now I have 6 weeks before bought a new SIGG bottle (because everyone else Nuk bottles were leaking and my daughter is now the SIGG bottles aufkriegt even himself). Yesterday I found that the internal coating had curled up (I thought the first for apple juice residue) in boiling water now completely detaches and after soaking. Funny. According Sigg should they not clean in the dishwasher, at our old bottles but that has never harmed. Must now take care of replacement - is annoying, because no matter how dense and great, the kindergarten bottle every night to wash by hand is already annoying.
