Everything was covered with soot and black sludge.

She held the torch up as her gaze narrowed at the pit of bubbling black sludge.

Prices are rising for the black sludge that helps make the world's gears turn.

The coffee machine was on, and there was a decent amount of black sludge in the carafe.

The floor of the little room was covered in black, undulating sludge.

It's not the actual crude oil, which is like a black sludge, that burns.

The accumulation of microbes appears as a black sludge or slime.

When broken open with a pinch bar, hammer and chisel, the safe was found to contain nothing but black sludge.

The stench originated with a resinous black sludge that had accumulated around him on the floor.

They waded through cold black sludge until they reached the entrance to the cave.