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general::
Phrase(s): leach away
[for something] to erode or wash away gradually by leaching. • The soft sandstone leached away under the constant rains. • The flowerpots sat out in the rain, where all the nutrients in the soil leached away., Phrase(s): leach something away (from something) [and] leach something out (of something); leach something out; leach something away
to remove something from something by leaching. • The heavy rains leached nutrients away from the soil. • The rains leached away the nutrients.
McGrawhill's American Idioms And Phrasal Verbs