The most common and most likely answer to this crossword clue is the 8 letter word SALVAGED
I've seen this crossword clue in The Guardian
S
A
L
V
A
G
E
D
Buddy explains!

The straight part
We know that "rescued" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rescued = salvaged.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 SALVAGED mean?
SALVAGED verb- (of property, people or situations at risk) to rescue.
- (of discarded goods) to put to use.
- To make new or restore for the use of being saved.