I think you're mixing up 3 different things:
1. Curing a gunked throat temporarily - Vocal Zone, or the other approximations mentioned above. Good for 1 hour's singing, not more.
2. Curing a gunked throat permanently - puke clears the mucus, honey cleans the surface, live yoghurt restores the correct blend. Salt water might make you puke, or enough whisky.
3. Stopping a throat getting gunked in the first place: healthy eating, plenty of fruit and veg, lemon and honey. Avoid the tube at rush hour. Get enough sleep.