They're used for stopping publicity (5)
I believe the answer is:
plugs
This clue is a double definition.
'they're used for stopping' is the first definition.
'publicity' is the second definition.
(a plug is a piece of publicity)
(Other definitions for plugs that I've seen before include "They'll stop" , "Stops up" , "stoppers" , "Wads, of tobacco say" , "Electrical connectors" .)