I just bought some of this. It claims that it can turn off color icing bright white again. Can anyone testify that this stuff works? Also, the bottle isn't too specific on how much to put in a batch of icing. Can anyone give me a ratio? TIA!!

I use either Wilton white or Americolor white to "whiten-up" my buttercream if I use butter. I usually add a little at a time until I get the color I want.