Wash off a little toddler in sea (5)
I believe the answer is:
rinse
'wash off' is the definition.
(I've seen this before)
'a little toddler in sea' is the wordplay.
'a little' indicates the answer is hidden within the clue (a little bit of the clue).
'RINSE' is hidden in the letters of 'toddler in sea'.
(Other definitions for rinse that I've seen before include "Hair tint" , "Sluice" , "Wash in clean water" , "Wash without using soap" , "Cleanse in water" .)