The most common and most likely answer to this crossword clue is the 6 letter word GETTER
G
E
T
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R
Buddy explains!
The straight part
We know that "Gas reducer" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gas reducer = getter.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 GETTER mean?
GETTER noun- One who gets.
- A function used to retrieve the value of some property of an object, contrasted with the setter.
- A material which is included in a vacuum system or device for removing gas by sorption.
- A miner who dug coal, contrasted with the putter, who took it to the surface.
- To remove gas by sorption.