Old tongue in tin can (4)
I believe the answer is:
inca
'old tongue' is the definition.
'inca' can be an answer for 'tongue' (language of the Incas). I'm not certain of the 'old' bit.
'in tin can' is the wordplay.
'in' indicates the answer is hidden within the clue.
'INCA' can be found hidden inside 'tin can'.
Can you help me to learn more?
(Other definitions for inca that I've seen before include "Ancient South American" , "Pre-conquest South American Indian" , "Old Peruvian descended from Cain" , "Andean culture" , "Member of old Peruvian Indian race" .)