Keep some journals to reminisce (5)
I believe the answer is:
store
'keep' is the definition.
(I've seen this before)
'some journals to reminisce' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'STORE' is hidden within 'journals to reminisce'.
(Other definitions for store that I've seen before include "Put by; shop" , "Save" , "Supply available for future use" , "Large shop; computer memory" , "Shop; hoard" .)