The most common and most likely answer to this crossword clue is the 4 plus 1 plus 7 letter word MADE A FORTUNE
I've seen this crossword clue in Independent
M
A
D
E
A
F
O
R
T
U
N
E
Buddy explains!
The straight part
We know that "cleaned up" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cleaned up = made a fortune.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.