scum

On Earth, such sediments have preserved evidence of ancient life in the form of fossilized mats of microscopic pond scum called stromatolites.

Intensely satisfying to use, these bad boys easily bust through even the grimiest, most built-up of messes—the soap scum on tubs, fat caked grill tops, and, of course, the toughest grout stains.

Scum it off with your spoon, and lay it in anotherPage 117 dish.

The home missions class furnished the inspiration for it, and called it "Scum o' the Earth," an impromptu immigration pageant.