Although I dont think melted chocolate could ever hurt anything, I have never tried it. I did want to let you know that when I make chocolate buttercream I just add cocoa and, instead of adding salt, I use salted butter and leave out the salt. For some reason, it seems bland to me when I do it the regular way. I have no idea why and it might only be a personal preference, but I thought I'd at least let you know. Happy Thanksgiving!