We’ll all agree that this is not as grand a change as, say, new window buttons or a new photo manager but what it is is end-user considerate. ‘Clean up’ could easily have lead many users to assume that the trash can was involved somewhere along the line. Swapping it out for an easily understandable way of describing what the action does is not only more intelligible to those less familiar with computing but just plain sense.
Like the addition of ‘Where is it?’ in the Ubuntu 10.10 Software Centre this is yet another small but important change that makes the Ubuntu desktop a user-friendly not user-scary place to be.