Airmail it off as well as old army collectables (9)

I believe the answer is:

militaria

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'old army collectables' is the definition.
(military items)

'airmail it off' is the wordplay.
'off' indicates an anagram.
'airmail'+'it'='airmailit'
'airmailit' anagrammed gives 'MILITARIA'.

'as well as' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.

Can you help me to learn more?

(Another definition for militaria that I've seen is " Special collection".)

I've seen this clue in The Independent.

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