In reply to bungle: Soaking it in bicarbonate of soda solution might help. Milton should certainly kill any nasties but it might not make it sparkly clean. Try pouring some neat down the tube, or soaking it in a small bowl of the stuff. Make sure you rinse it thoroughly afterwards.
Best advice is always to rinse it thoroughly and let it dry properly after using it each time - hang it over a radiator or in the airing cupboard, if you have one. Try to hang it up in a way which encourages a bit of air flow through the tube eg hanging vertically rather than coiled.