Old comic afterwards trimmed and in fine fettle (3,5)

'old comic' is the definition.
'the dandy' can be an answer for 'comic' (I've seen this before). I am unsure of the 'old' bit.

'afterwards trimmed and in fine fettle' is the wordplay.
'afterwards' becomes 'then' (I've seen this before).
'trimmed' means to remove the last letter (the last letter is trimmed off).
'and' means one lot of letters go next to another.
'in fine fettle' becomes 'dandy' (I can't explain this - if you can you should believe this answer much more).
'then' with its final letter taken away is 'the'.
'the'+'dandy'='THE DANDY'

Can you help me to learn more?