The most common and most likely answer to this crossword clue is the 6 letter word SHAWMS
S
H
A
W
M
S
More clues leading to the result SHAWMS
Buddy explains!

The straight part
We know that "instruments of the past" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case instruments of the past = shawms.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.
What does SHAWMS mean?
SHAWMS noun- A mediaeval double-reed wind instrument with a conical wooden body.