Sistema Twist N Sip Squeeze Bottle 330ml & 460ml

This is a great bottle - it does not leak.Critically, it is BPA-free. BPA (bisphenol A) is often present in polycarbonates (which this type of bottle is made from). BPA is found in many plastics and may be linked to cancer. It is an unstable compound and can leach into food products. Once in food, BPA can move quickly into people - a particular concern for women of childbearing age and young children. So, it pays to buy BPA-free plastics for plastics used with food.It has one problem. You soon get black mould forming inside the lid which we found impossible to remove because you cannot reach it.So we bought another bottle - which succumbed to the identical problem.The problem is caused by the fact that you cannot dismantle the lid - you cannot reach the parts inside the lid through which water flows. Therefore you cannot clean the internal parts of the lid.May I suggest that, as mould needs water to form, to slow down the rate of mould formation do not leave liquids in the bottle for any longer than necessary. For the same reason, after washing it, we stored the lid separate from the bottle (not screwed onto it) and in the `drinking' position (i.e. we twisted the ring on the cap, so that the drinking nozzle rises - this allows air to flow through the nozzle, so that the water inside evaporates).Someone kindly gave us a tip that the solution is to immerse it regularly in `Milton'. I am grateful to him because this has solved the problem.This is a great bottle.