Plasticine was a material which school art rooms often held.
Ace convinced her secondary school art teacher, Mrs Parkinson, that Ace's homemade gelignite was school plasticine, and Mrs Parkinson made the grave mistake of taking it back into the art room. Ace then threw a live grenade into the art room, which landed and exploded "right in the middle of Class 1C's prize-winning pottery pig collection". (TV: Battlefield) Ace was suspended for blowing up the art room. (TV: Dragonfire)
Behind the scenes[]
Plasticine is a brand of modelling clay.