The most common and most likely answer to this crossword clue is the 6 plus 3 plus 5 letter word BUCKET AND SPADE
I've seen this crossword clue in Financial Times
B
U
C
K
E
T
A
N
D
S
P
A
D
E
Buddy explains!
The straight part
We know that "them" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case them = bucket and spade.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.