You may want to go to Hobby Lobby or Michaels and look at the butterflies that they sell....come in different sizes and colors, pretty good looking and will take some abuse over the years. I used to shade them a little and they were fine for commercial work.
A real Monarch butterfly, (even if allowed in your state) preserved properly or not, probably won't stand up to any commercial abuse as the wings and legs would be very fragile...if I were to use one, it would be on a mount in a glass case to protect it.
