The most common and most likely answer to this crossword clue is the 8 letter word SILVERED
I've seen this crossword clue in Independent
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More clues leading to the result SILVERED
Buddy explains!
The straight part
We know that "went grey" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case went grey = silvered.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SILVERED mean?
SILVERED verb- To acquire a silvery colour.
- To cover with silver, or with a silvery metal.
- To polish like silver; to impart a brightness to, like that of silver.
- To make hoary, or white, like silver.
- Coated with silver, made reflective or shiny by application of metal.