Nigre definitions

Nigre

1) Soap residue
Found on https://www.crosswordclues.com/clue/nigre

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nigre

(from the article `soap and detergent`) ...to separate into two layers. The upper layer is neat soap, sometimes called kettle soap, of almost constant composition for a given fat (about 70 ...
Found on http://www.britannica.com/eb/a-z/n/41

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