Also found a Google reference to slue / slough, and the following (US) definitions for slough:[
n] any outer covering that can be shed or cast off (such as the cast-off skin of a snake)
[n] a stagnant swamp (especially as part of a bayou)
[n] a hollow filled with mud
[n] necrotic tissue; a mortified or gangrenous part or mass
[v] cast off hair, skin, horn, or feathers; of animals
Not sure if that gets you anywhere!
Paul