Ash blondes could be old ones (6)
I believe the answer is:
flames
'ash blondes' is the definition.
Although both the answer and definition are plural nouns, I don't see how one could define the other.
'be old ones' is the wordplay.
I cannot really understand how this works, but
'be' could be 'am' and 'am' is found within the answer.
This explanation may well be incorrect...
'could' acts as a link.
Can you help me to learn more?
(Other definitions for flames that I've seen before include "Blazes, flares" , "Insulting emails" , "Hot glows from the fire" , "Glowing bodies of ignited gas generated by fire" , "exes!" .)