Nothing wrong with the last thing that is used for a soup? (6)
I believe the answer is:
oxtail
'a soup?' is the definition.
(oxtail soup is a kind of soup)
'nothing wrong with the last thing' is the wordplay.
'nothing' becomes 'O' (looks like zero - 0).
'wrong' becomes 'x' (X is used to mark something as incorrect).
'with' says to put letters next to each other.
'the last thing' becomes 'tail' (I can't explain this - if you can you should believe this answer much more).
'o'+'x'+'tail'='OXTAIL'
'that is used for' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for oxtail that I've seen before include "A brown soup" , "Cattle appendage used to make tasty soup" , "Soup base" , "Soup ingredient" , "Part of cattle, used especially in soup" .)