The most common and most likely answer to this crossword clue is the 6 letter word ZLOTYS
I've seen this crossword clue in Financial Times
Z
L
O
T
Y
S
More clues leading to the result ZLOTYS
Buddy explains!

The straight part
We know that "Polish ready" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case polish ready = zlotys.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 ZLOTYS mean?
ZLOTYS noun- Złoty, the currency unit of Poland, divided into 100 groszy.