Mums dropping others like hot potatoes (4)
I believe the answer is:
mash
'potatoes' is the definition.
(mashed potato)
'mums dropping others like hot' is the wordplay.
I cannot really see how this works, but
'mums' could be 'mas' ('ma' can be a synonym of 'mum') and 'mas' is found within the answer.
'hot' could be 'h' (abbreviation eg on taps) and 'h' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for mash that I've seen before include "Forces hospital" , "It goes well with sausages" , "food for animals" , "Pulped potatoes" , "Black comedy film set in Korean War" .)