Spotless old instrument (8)
I believe the answer is:
virginal
I believe this clue is a double definition.
'spotless' is the first definition.
(both can mean pure or untouched)
'old instrument' is the second definition.
(historical keyboard instrument)
(Other definitions for virginal that I've seen before include "Unblemished" , "spotless" , "in immaculate condition" , "Rectangular harpsichord" , "Antique keyboard" .)