The eight brushes given by Bacon to fellow artist Clive Barker in 1978 are in a paint-splattered butter bean tin inside a clear box. They have an estimated price of 20,000 pounds to 25,000 pounds ($31,000 to $46,000).
Bacon's paintings have sold for as much as $86 million at auction.
Also among the 150 lots in Christie's Out of the Ordinary sale: a rocking horse as tall as a house; a flying machine from Steven Spielberg's "Young Sherlock Holmes"; a stuffed ostrich; and a Triceratops skull valued at between 150,000 pounds and 250,000 pounds.
The sale will be held Sept. 5 in London.