Possible Clues:

• Vacant sign seen on long grass
• Inform of allergic reaction to tin?
• Untrustworthy one
• One informing idiot’s in school
• Steal from school, carrying can back
• Tell tales of louse’s egg found in school
• Poles must anticipate urge to grass
• Whistleblower (informal)
• Inform
• Idiot in school who betrays classmate?