The joke will be a short and light one
I imagine it with my daughter:
She (scribing): Dad, the glass of the monitor is cracked
Me: What what?! Where?... ...Yes it is!
She: But I don't feel it under my nail...
Me (scribing too): Hmm... Evidently it's on the inner side of the glass.
She: What we do now?
Me: Well... thinking on buying a new one?
(Thinking) Well it's some dangerous, it could explode (it's 21 inches CRT). Sigh... I'll take the risk and work with it till we buy a new one... But what about you?
(she is often working in my account, so...)
The scratches disappeared
Me: Hmm... They certainly did it with a self-healing glass...