dross vs scrapheap

dross

noun
  • A waste product from working with metal. 

  • Worthless or trivial matter. 

  • The impurities in metal. 

  • Waste or impure matter. 

  • Residue that forms on the surface of molten metal from oxidation. 

verb
  • To remove dross from. 

scrapheap

noun
  • A pile in which junk is discarded. 

  • A junkyard. 

  • A collection of discarded or rejected items or ideas. 

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