Adhesive label used by staff with queen (7)
I believe the answer is:
sticker
'adhesive label' is the definition.
(I've seen this before)
'staff with queen' is the wordplay.
I cannot quite see how this works, but
'staff' could be 'stick' (I've seen this before) and 'stick' is found in the answer.
'queen' could be 'er' (abbreviation for Elizabeth Regina) and 'er' is located in the answer.
No letters remain.
This explanation may well be incorrect...
'used by' acts as a link.
Can you help me to learn more?
(Other definitions for sticker that I've seen before include "Determined person" , "Person with staying power" , "Gummed label" , "he soldiers on!" , "problem" .)