Drug put in lost waste disposal facility (7)
I believe the answer is:
ashtray
'waste disposal facility' is the definition.
(receptacle for cigarette ash)
'drug put in lost' is the wordplay.
'drug' becomes 'h' (H is an example).
'put in' means one lot of letters goes inside another.
'lost' becomes 'astray' (synonyms).
'h' put into 'astray' is 'ASHTRAY'.
(Other definitions for ashtray that I've seen before include "Receptacle for tobacco detritus" , "debris receptacle" , "Place for detritus from cigarettes, cigars etc" , "Receptacle for cigarette butts" , "Place for cigarette ends" .)