Random FactsCuriousOneJanuary 24, 2017combust, fact, facts, grass, hay, left, piles, spontaneously, staycurious, wetComment Wet hay or grass can spontaneously combust when left in piles Random FactsCuriousOneJanuary 24, 2017combust, fact, facts, grass, hay, left, piles, spontaneously, staycurious, wetComment