Is there a way of protecting a worksheet so that you cannot paste data into it.

I have a column of data and a validation list to select from short name
months Jan-Dec, however some people are pasting in full month names, which
means I then have to change them before I can create pivot tables on the data.

This can be very time consuming when I am receiving many sheets from various
sources, and trying to collate everything together.

Many Thanks in advance