To gather information sneakily; to seek out information without revealing that one is looking for it.
To grope; to explore an area with one's hands, usually in search of something.
To collect and remove refuse, or to search through refuse, carrion, or abandoned items for useful material.
To expel the exhaust gases from the cylinder of an internal combustion engine, and draw in air for the next cycle.
To remove unwanted material from something, especially to purify molten metal by removing impurities.
To feed on carrion or refuse.