### Clue: Preserved sandwiches of last month it's learned (8)
### Answer: CULTURED 
 ### Explanation: Definition: learned
 CURED(preserved, as with meat) **containing**(sandwiches) ULT(abbrev. for "ultimo", of the last;previous month to the current one).
Defn: Descriptive of someone or something that is well-informed;scholarly, as in "a learned literary journal".