Hello amazing cake artists! I've been admiring many cakes on this site for a long time - you are all wonderful!
My wedding cake was buttercream with gumpaste flowers on it. All of the flowers were saved. I would like to know how to remove the buttercream (it's a shortening base and hasn't fully dried 3 months later). I hope to be able to put all the flower arrangements together in a bouquet, and put it in a shadow box for keeps.
Welcome to CC.
Fortunately I've never had to deal with this. Due to the nature of gumpaste, I wouldn't want to use anything liquid on it, in fact, I'd even worry about using Vodka which evaporates rapidly. Perhaps someone else might have luck with it... You, however, might want to try it on a smaller, maybe insignificant flower-- (although coming from your wedding cake that might not be an appropriate adjective ). You might even have luck with that same experimental flower using a small stiff brush. A pig bristle brush comes to mind, carefully working the BC off.
I hope someone else can direct you to a satisfactory solution. Having a bouquet of your wedding flowers would be a wonderful keepsake. Whatever you do, remember to keep it free from dust and out of direct light to best preserve your memories.