Before the end of the day over half of the class get the dirt (4)
I believe the answer is:
clay
'the dirt' is the definition.
(clay is a kind of dirt)
'before the end of the day over half of the class' is the wordplay.
'before' is a charade indicator (letters next to each other).
'the end of the day over' becomes 'lay' (I can't justify this - if you can you should give a lot more credence to this answer).
'half of' suggests halving the letters.
'the class' becomes 'cl' (I've seen this in other clues).
'cl' with half the letters taken is 'c'.
'lay' after 'c' is 'CLAY'.
'get' is the link.
Can you help me to learn more?
(Other definitions for clay that I've seen before include "Sticky earth; human substance (poet.)" , "Court surface" , "Pigeon target" , "Material for idol's feet?" , "Muhammad Ali's original surname" .)