elute vs leach

elute

verb
  • To separate one substance from another by means of a solvent; to wash; to cleanse. 

leach

verb
  • To purge a soluble matter out of something by the action of a percolating fluid. 

  • To part with soluble constituents by percolation. 

noun
  • A tub or vat for leaching ashes, bark, etc. 

  • A jelly-like sweetmeat popular in the fifteenth century. 

  • A quantity of wood ashes, through which water passes, and thus imbibes the alkali. 

How often have the words elute and leach occurred in a corpus of books? (source: Google Ngram Viewer )