It would not undo any formatting, only values.

Secondly it would probably be best to keep it to only being able to undo values in the range "C5:C14".

When you referred to 'undo' I wasn't sure if you meant for the whole sheet or just your specific range of "C5:C14"?

If you wanted it to work for the sheet tli suppose that would depend how heavily used the sheet is, I.e. are you pasting large blocks of data or if one cell is edited at a time?

If it was to clear the old values out that are stored next to the target cell then it would most certainly need to be restricted to your range of "C5:C14" if that makes sense.

I, or someone else could look at this but I am only on my phone at the moment.