They show that the Jackson children loved their dad and they weren't afraid to express it.
Prince, now 14, Paris, 13, and Blanket, nine, wrote on a tiny kitchen blackboard the phrase 'I love Daddy' twice, substituting the word 'love' for a childish heart symbol. And underneath they wrote: 'Smile, it's for free.'
The scribblings came to light as items were being prepared for sale from Jackson's former rented home in Bel Air, California, on Dec 17.
But while these small symbols of normality suggest the Jackson brood lived ordinary, happy lives, another inscription suggests their father was deeply driven.
On an armoire, scribbled across a mirror is, is the message: 'Train, perfection, March, April, Full Out, May!'
Julien's Auctions - who are holding the sale - say Michael wrote the message to himself to give him motivation for his anticipated This Is It tour.
Among other items for sale are upholstered chairs smudged with Jackson's makeup and his deathbed.