Add a VOID() worksheet function
VOID(p1, ..., pn) where each parameter is a cell or a range
It deletes the contents of the specified cells and returns the number of cells whose values are cleared (similar to the return value of COUNTA() before the cells are cleared)
It is suggested as an alternative to the NULL() function requested by others and hasn't been implemented yet, presumably due to some technical challenges.
The VOID() function is different in that it does not require a cell's content to be cleared by assigning a value, which sounds like a contradiction in terms.