White ash a sign of good quality?

Cannabis cultivators and connoisseurs have come to believe that, like the white smoke seen in St. Peter’s Square, white ash left behind in the bowl from smoking cannabis is a cause to celebrate. Black ash, they believe, signifies that the plant was not flushed to remove minerals, nitrates and pesticides. White ash, in contrast, symbolizes properly flushed, dried and cured material. True or false?