Freeze
surprisingly,you can freeze hot water quicker than cold.
This is called the MpemBa effect with evaporation playing a big part.
When hot water begins to cool,some of the water evaporates,causing an overall decrease in the mass.
With less water to freeze,the process takes less time.
Another reason is that hot water contains less dissolved gas,reducing its ability to conduct heat.
In addition,when hot water rises,displacing the cold water beneath,it creates a convection current causing the temperature of the hotter water to drop faster than the cooler water.
However,this works only when using an open container