If you do a Ctrl-X in a cell that will remove all the contents (including
the formatting).
If you want to leave the formatting in a cell (like a yellow background and
a black border box for example) copy the contents of that cell (Ctrl-C) then
paste them into the cell into which you wish to copy. If you then go back to
the first cell and hit delete you will remove the data (for example a number
1) but leave the formatting (for example a yellow background and a black
border box).
If my comments have helped please hit Yes.
Thanks.