Sponge found in toilet, note (6)
I believe the answer is:
loofah
'sponge' is the definition.
(I've seen this before)
'toilet note' is the wordplay.
'toilet' becomes 'loo' (loo is a kind of toilet).
'note' becomes 'fah' (fourth note in sol-fa notation, anglicized version).
'loo'+'fah'='LOOFAH'
'found in' acts as a link.
(Other definitions for loofah that I've seen before include "Back scrubber" , "Bathroom sponge made of halo" , "Dried part of plant used as a bath sponge" , "Dry sponge used for scrubbing" , "Bathroom sponge for washing back" .)