Contain an oil-like substance called bitumen

Tar sands.

Explanation:

Tar sands also called as oil sands, it is defined as the mixture of mostly clay, water, tar sand, and a molasses like substances known as bitumen. Bitumen is composed of hydrocarbons in liquid oil in same molecules, and it is mainly used for produce gasoline, and other petroleum products.

Extracting bitumen is significantly more difficult, and costlier compared to other extracting refining liquid oil. Common extraction method of bitumen includes surface mining.

kuchisake

kuchisake-onna (口裂け女, "slit mouth woman ") is a malevolent figure appearing in japanese ghost stories, possibly dating back to the edo period. she takes the form of a masked woman who approaches people and asks them if they believe she is pretty.

explanation:

it's filtration, but this is an assumption so my apologies if i got this