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		#4 | 
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			Join Date: Jan 2008 
				
				
				
					Posts: 1,429
				 
				
				
				
				
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			I read somewhere (can't remember where) that this black, sooty surface film was deliberately applied in Africa, as a type of preservative... 
		
		
		
		
		
		
		
	Its a similar surface film/residue to that found on the inside of traditional African hut roofs, being formed from the cooking fire.  | 
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