Where dam's found scrubbing a pen? (4)
I believe the answer is:
swan
'pen?' is the definition.
(pen is a female swan)
'where dam's found scrubbing a' is the wordplay.
I cannot really understand how this works, but
'a' could be 'an' and 'an' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for swan that I've seen before include "Whooper or trumpeter?" , "Sweet name 8 [OF SHAKESPEARE]" , "Large waterbird" , "Stately aquatic bird" , "The Ugly Duckling's outcome" .)