To form a scum on the surface.
The word "scum" can have a derogatory connotation, referring to a low or despicable person. It can also mean a layer of dirt or froth that forms on the surface of a liquid.
The word is "scum."
kasu
Dross - solid metal scum or debris floating on molten metal
scum
Dross is a term used to describe impurities or scum that float on the surface of molten metal.
Sludge and scum usually contain bacteria, but the terms do not mean bacteria, they just mean sticky, gooey, messy, nasty, filthy substances.
Pest, Menace, Scum ...
Scatter
Svoloch means "Scum." Are you wondering this from Call of Duty?
figure it out u big scum bag..........