Have you ever accidentally created an unnecessary column in a table in your report? You ended up with a column called "MyCustomColumn" that has nothing in it? You tried clicking the column and hitting delete? You tried right-clicking, to no avail? How can you get rid of those pesky columns? This is a question I'm often asked in my reporting classes.
When you add a custom column to your table, whether you name it or not, it gets added to the values area of the Ad Hoc Query Configuration dialog. That means, in order to remove it from your table all you have to do is find it in the Configuration dialog, right click and choose Remove.