Explicitly told them it was dry-cleaned before leaving New York (8)
I believe the answer is:
declared
'explicitly told' is the definition.
'declared' can be an answer for 'told' (declaring is a kind of telling). I'm unsure of the 'explicitly' bit.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for declared that I've seen before include "Announced, proclaimed" , "Closed an innings" , "Stated emphatically" , "Spoke or said dramatically" , "Announced publicly" .)