The youth, aged 14, was charged with assault arising out of the incident.
The court heard the teenager asked the staff member for his nasal spray, but when he handed it back he rubbed faeces on the man’s hand.
The injured party said he told him to stop and went to his office, but the boy had also smeared it on the the door handle, which the man then got on his other hand.
When the worker asked the boy to stop “he just laughed”
Solicitor Sarah Ryan said it was her client’s case the substance was in fact Nutella, but the injured party replied “It was definitely faeces, I could smell it”.
When asked whether he had done it, the boy told gardaí it was his “way of getting back at staff”.
The teen told Judge Marian O’Leary he “wouldn’t do that” and said it was Nutella on his hand and on the door.
Asked why he admitted to the offence to gardaí he replied “I didn’t realise what I was saying yes to”.
The judge found him guilty and adjourned the matter.