Sticky substance in drinking vessel recalled (3)
I believe the answer is:
gum
'sticky substance' is the definition.
(I've seen this before)
'drinking vessel recalled' is the wordplay.
'drinking vessel' becomes 'mug' (mug is a kind of drinking vessel).
'recalled' says the letters should be written in reverse.
'mug' written backwards gives 'GUM'.
'in' acts as a link.
(Other definitions for gum that I've seen before include "Leaving body" , "surrounding roots of teeth?" , "Sticky substance and mouth tissue" , "Part of mouth; a tree" , "Eg, a eucalyptus" .)