Odd characters in Cape Town ignored for many years (4)
I believe the answer is:
aeon
'years' is the definition.
(aeon is a kind of years)
'odd characters in cape town' is the wordplay.
'odd characters in' means one should take alternating letters (the letters at odd-numbered positions).
'cape'+'town'='capetown'
The alternating letters of 'capetown' are 'AEON'.
'ignored for many' is the link.
This may not be right. Some or all of it may belong to another bit of the clue.
(Other definitions for aeon that I've seen before include "A very long time, an age" , "Immeasurably long period of time" , "An immense period of time" , "Epoch" , "Longest division of geological time" .)