Just a suggestion but I keep accidentally posting my crafts as sandboxes because I post them while on Droo so I can have a better thumbnail for my post. However, as soon as I realize this my crafts are stuck in a sanbox and I never saved them. Asking for a feature to save crafts from snadbox..
You can do this manually, if you go to the game files and go into a GameState folder, you can find the xml files of your crafts there. Depending on some factors they may not work. btw, please, post suggestions in the suggestions section and not as bug reports