There is a easy way to remove unwanted workspace in Eclipse Juno, from the workspace list. Here is the way to do that in 5 seconds.
If you want to not make Eclipse suggest that old workspace, you’ll need to edit the “org.eclipse.ui.ide.prefs” file in the “configuration/.settings” directory under your installation directory (or in ~/.eclipse on Unix, IIRC).
Remove the unwanted workspaces in the “RECENT_WORKSPACES” property list.
Note: Make sure the final workspace name should not have any special charaters/symbols, on its tail.