Means to preserve obscure terms from the jazz age - oddly forget 'splitting' (4-6)
I believe the answer is:
deep-freeze
'jazz age oddly forget splitting' is the definition.
I can't judge whether this definition defines the answer.
'means to preserve obscure terms from' is the wordplay.
I cannot really understand how this works, but
'obscure' could be 'deep' (I've seen this in another clue) and 'deep' is present in the answer.
'from' could be 'fr' (abbreviation) and 'fr' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'the' acts as a link.
Can you help me to learn more?
(Other definitions for deep-freeze that I've seen before include "Cold food storage unit" , "Large iced food store" , "Store in ice" , "Refrigerator cabinet" , "Store at a very low temperature" .)