The most common and most likely answer to this crossword clue is the 11 letter word SHOP-SOILED
I've seen this crossword clue in The Times
S
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More clues leading to the result SHOP-SOILED
Buddy explains!
The straight part
We know that "Does polish alter the look of such merchandise" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case does polish alter the look of such merchandise = shop-soiled.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 SHOP-SOILED mean?
SHOP-SOILED adjective- Soiled from display in a shop; shopworn.