Container of burnt remains (3)
I believe the answer is:
urn
'container' is the definition.
(I know that urn is a container)
'of burnt remains' is the wordplay.
'of' indicates the answer is hidden within the clue.
'URN' can be found hidden inside 'burnt remains'.
(Other definitions for urn that I've seen before include "Receptacle for human ashes" , "Receptacle for ashes of the dead" , "Ossuary" , "Burial vase" , "One carrying coffee or tea" .)