Blu-tack.

'Do you realise how dangerous Blu-Tack is? I must admit that I didn't! That is I didn't know of its dangers, until I read in a survey of teachers that some unnamed teacher .... at an unnamed school told staff and children to wear goggles when handling Blu-Tack. Why are people like this allowed anywhere near children?'

A LoonyyTuneswatch coconut is hereby awarded to these doyens of common sense
- should they dare to make themselves known!

Wrested from 'Nanny Knows Best' - with thanks.