SCAVENGING

To collect and remove refuse, or to search through refuse, carrion, or abandoned items for useful material

To remove unwanted material from something, especially to purify molten metal by removing impurities

To expel the exhaust gases from the cylinder of an internal combustion engine, and draw in air for the next cycle

The act of searching through refuse for useful material.

"Our scavengings at the rubbish dump often yielded items of value."

That eats carrion