The most common and most likely answer to this crossword clue is the 6 letter word TOTALS
I've seen this crossword clue in Independent
T
O
T
A
L
S
More clues leading to the result TOTALS
Buddy explains!

The straight part
We know that "Destroys" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case destroys = totals.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 TOTALS mean?
TOTALS noun- An amount obtained by the addition of smaller amounts.
- Sum.
- To add up; to calculate the sum of.
- To equal a total of; to amount to.
- To demolish; to wreck completely. (from total loss)
- To amount to; to add up to.