After zesting some fruit skins I juiced the remainder of the fruit and put it in the fridge in a flagon with the intent of adding it to a ferment. After dumping the juice in the ferment the next day I tried to clean the flagon with hot water...
No way was it going to move.... it was caked on.
The answer.... use a tradies trick to clean their thermos with rice and cold water.
In this case you add rice and cold water to the flagon and shake like hell.
It worked with no drama..