What is the meaning of scavenged

verb (used with object), scav·enged, scav·eng·ing.

to take or gather (something usable) from discarded material. to cleanse of filth, as a street. to expel burnt gases from (the cylinder of an internal-combustion engine). Metallurgy. to purify (molten metal) by introducing a substance that will combine chemically with impurities.

verb (used without object), scav·enged, scav·eng·ing.

to act as a scavenger.

collect from discarded waste