These are the best labels for re-labeling items that have old labels that cannot be removed. Also, once these labels are placed over old labels that do not come off.
I recently found out about Avery's new shipping labels that you can place over old shipping labels and they completely opaque the old label. This is a great idea so you can re-use (recycle) a box without having to scribble out the old address label with a permanent marker or use a bunch of blank labels to hide the old label.