scavenge

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To search through for salvageable material: scavenged the garbage cans for food scraps.
2. v. To collect and remove refuse from: The streets are periodically scavenged.
3. v. To collect (salvageable material) by searching.
4. v. To expel (exhaust gases) from a cylinder of an internal-combustion engine.
5. v. To expel exhaust gases from (such a cylinder).
6. v. Metallurgy To clean (molten metal) by chemically removing impurities.
7. v. To search through refuse for useful material.
8. v. To feed on dead or decaying matter.

Century Dictionary and Cyclopedia

1. To cleanse from filth.
2. In certain forms of the internal-combustion motor, to sweep out of (the cylinder) by an inrush of atmospheric air the burnt products of the previous combustion-stroke. By thus cleansing or scavenging the cylinder the fresh intake of combustible mixture is not diluted with incombustible gases, nor is it heated by them so as to contain less weight of fuel per cubic foot of volume.

Wiktionary

1. v. transitive to collect and remove refuse, or to search through refuse for useful material
2. v. transitive to remove unwanted material from something, especially to purify molten metal by removing impurities
3. v. transitive to expel the exhaust gases from the cylinder of an internal combustion engine, and draw in air for the next cycle
4. v. intransitive to feed on carrion or refuse

GNU Webster's 1913

1. v. To cleanse, as streets, from filth.
2. v. to salvage (usable items or material) from discarded or waste material.
3. v. To remove (burned gases) from the cylinder after a working stroke.
4. v. (Internal-combustion Engines) To remove the burned gases from the cylinder after a working stroke.

WordNet 3.0

1. v. collect discarded or refused material
2. v. remove unwanted substances from
3. v. feed on carrion or refuse
4. v. clean refuse from