Just to make it easier to find, here's Tracy's nifty little trick for hiding the ABC of empty columns:

I can't remember where I posted it either! I'll make a KB article regarding this so it will be easier to reference (I think the post was lost in a thread with a different subject).

To get rid of the Abc, create a blank calculation using a space between two quotes:

" "

Then, place it on the text shelf. If need be, it can also be placed on the columns shelf, then right click on it and un-check Show Header.

Hope this helps!

-Tracy