What's left at the bottom of shelter close to Calais (4)
I believe the answer is:
lees
'what's left' is the definition.
I can't tell whether this definition defines the answer.
'at the bottom of shelter close to calais' is the wordplay.
'at the bottom of' is a charade indicator (letters next to each other).
'shelter' becomes 'lee' (as in lee side, the side sheltered from wind).
'close to' says to take the final letters (the 'close' to the word).
The final letter of 'calais' is 's'.
'lee' put next to 's' is 'LEES'.
Can you help me to learn more?
(Other definitions for lees that I've seen before include "Dregs of drink" , "Wine at bottom of glass" , "Wine dregs" , "Sediment that settles at the bottom of wine" , "Sediment from fermentation of alcohol" .)