Lovely cleaner of high-quality porcelain (8)
I believe the answer is:
charming
'lovely' is the definition.
(thesaurus)
'cleaner of high-quality porcelain' is the wordplay.
'cleaner of' becomes 'char' (I can't justify this - if you can you should believe this answer much more).
'high-quality porcelain' becomes 'ming' (porcelain made in China during the Ming dynasty).
'char'+'ming'='CHARMING'
(Other definitions for charming that I've seen before include "Beguiling, enchanting" , "Lovely! - with 15a" , "Delightful, attractive" .)