Possible Clues:

• Start-over button
• Turn the tripmeter to 000
• Can this be chopped in bits and planted somewhere else?
• Change typeface, for example, or fifteen in another direction
• Appliance button
• Restore state of sapper on location of shooting
• Change, as a watch
• Microwave button
• Button you might have to poke with a paper clip
• Change the alarm clock