Moving some video files around I mistakenly pushed them onto the applications/places toolbar. There they stay. I can't get rid of them. (Ubuntu 12.04 LTS)
/home/peter/Pictures/Screenshot from 2013-04-12 13:33:56.png
I beleive you are talking about the launcher.
Right-click the icon you want.
Click 'Remove from launcher'.
It should dissapear.
The top bar
Right-click the menu bar. Click 'Edit Menu's...'
Find the file you want and delete it.
Hope this helps!!!