rumors say that itll take out runes made from dups, runewords containing dups ect..
all of the runewords i made survived the last ruststorm on uswest
lastwish (most likely to have 6dups), fort, delerium
lost a mal and ohm tho
runewords that poofed were probably entire duped runewords
the odds of your dups staying depend on how many of each dup are on bnet
ruststorm is supposed to save one of each dup
so if only 2 of them exist, then 1 will stay
if hundreds are out then the odds of yours staying is greatly decreased
sometimes it takes out just the runeword and youre left with a near useless item with runes in it. doesnt happen as often though. most of the time the entire item is gone. it happened to me and my friend. i was left with "tir" instead of "tirel" (i cant believe someone actually duped an el rune.) and my friend was left with a useless former botd.