The most common and most likely answer to this crossword clue is the 7 letter word OXIDISE
I've seen this crossword clue in Financial Times
O
X
I
D
I
S
E
More clues leading to the result OXIDISE
- Cross after ring has one side deformed and become rusty
- That’s nothing. Take it easy. Not even I’d get cross about rust
- Neat papers I see briefly will burn
- Incinerate bovine creature with current... dies violently
- Burn in love side by side, intertwined
- During Noel essentially detectives on team become rusty
Buddy explains!
The straight part
We know that "become rusty" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case become rusty = oxidise.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 OXIDISE mean?
OXIDISE verb- To combine with oxygen or otherwise make an oxide.
- To increase the valence (or the positive charge) of an element by removing electrons.
- To coat something with an oxide.
- To become oxidized.