Removes crusted matter from stinking sled case (8)

I believe the answer is:

descales

I'm a little stuck... Click here to teach me more about this clue!

'removes' is the definition.
(descaling is a kind of removing)

'crusted matter from stinking sled case' is the wordplay.
'sled case' can be anagrammed to 'DESCALES'.
But, I'm not clear how this is indicated.

Can you help me to learn more?

I've seen this clue in The Everyman puzzle in The Observer.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.