It might be easier to just upload a song file with only the instrument in it? I don't use Live much (I have a lite version I got for free with my midi keyboard). But I assume you mean things like sampler patches and other instruments in Live.
Which version? In 9 if you go into your user library and find the saved instrument group you can right click (cmd-click) and "Show in Finder" You might also try searching for .adg files.
Also when I saved a rack it showed up in /Users/sulihin/Music/Ableton/User Library/Presets/Instruments, so check there! (replacing sulihin with your user name of course....)