Corflu

(Did you mean the convention?)

Corflu is a scientificombination for correction fluid, a liquid used to cover up typos on mimeo stencils just prior to inserting newer errors. One famous brand was Obliterine (which see for details on its use).

In The Enchanted Duplicator, the Spirit of Fandom gives a bottle to Jophan, telling him, "Here is a bottle of a magic liquid called Correcting Fluid. A touch of this will instantly heal any wound made by a typo."