scavenge
Concise Oxford English Dictionary © 2008 Oxford University Press:
scavenge /ˈskavɪn(d)ʒ/
▶verb
- 1 search for and collect (anything usable) from discarded waste.
■ search for (carrion) as food.
- 2 remove (combustion products) from an internal-combustion engine cylinder on the return stroke of the piston.
- 3 Chemistry combine with and remove (molecules, radicals, etc.) from a particular medium.
'scavenge' also found in these Oxford entries:

