I did the same by accidentally forgetting to wire a 5v regulator and fed 24v directly into the BT. The sparks blew a distance of about 1 foot, followed by blue smoke, it was quite spectacular!
The BT radio comes out quite easily, but there isn't much left to get solder onto and the spacing is too tiny for my soldering skills so it's been sitting here gathering dust.
If you figure out a way to salvage it and post details that would be great - best of luck 