Crossword Genius

Useless stuff repaired with a teen’s help (5,9)

Ross

I believe the answer is:

white elephants

I'm a little stuck... Click here to teach me more about this clue!

'useless stuff repaired' is the definition.
I can't tell whether this defines the answer.

'with a teen's help' is the wordplay.
I cannot really see how this works, but
an anagram of 'with' is 'whit' which is within the answer.
'a' could be 'an' and 'an' is located in the answer.
an anagram of 'help' is 'leph' which is located in the answer.
This explanation may well be incorrect...

Can you help me to learn more?

I've seen this clue in The Sunday Times.
Want a hint initially instead of a full solution? Install my app