Should a burnt corpse be washed, and how should it be washed if the burning is complete?

One who died by burning, if it is possible to wash them, should be washed. If there is fear of their body disintegrating or breaking apart during washing, then water should be poured over them. If there is fear of their body breaking apart even by pouring water, then tayammum (dry ablution) should be performed if possible. If washing is not possible, tayammum should be performed.

Ibn Qudamah said: "One who died from smallpox, burning, or drowning should be washed if possible. If there is fear of their body disintegrating during washing, water should be poured over them without touching. If there is fear of their body breaking apart even by water, then they should not be washed but rather tayammum should be performed if possible, just as a living person who is harmed by water performs tayammum."

Sheikh Ibn Baz was asked about how to wash someone who died in an accident and whose body was disfigured. He replied: "It is obligatory to wash them if possible, otherwise, tayammum should be performed."

It is stated in the Fatawa of the Permanent Committee regarding someone whose body was dismembered in an accident: "If washing is impossible, tayammum should be performed, based on the Almighty's saying: (So fear Allah as much as you are able), and because tayammum was legislated for purification when water is unavailable or one is unable to use it."