Various ashtrays emptied — problem solved! (8)
I believe the answer is:
assorted
'various' is the definition.
(synonyms)
'ashtrays emptied problem solved' is the wordplay.
'emptied' suggests removing the centre.
'problem solved' becomes 'sorted' (both might be said after a difficulty is resolved).
'ashtrays' with its middle removed is 'as'.
'as'+'sorted'='ASSORTED'
(Other definitions for assorted that I've seen before include "Manifold" , "Miscellaneous, sundry" , "Various, diverse" , "Of different kinds put together, like sweets" , "Odd-shaped" .)