For those of you who use a drum sander you know that sometimes you'll get snipe just like on a planer. The quick trick to eliminating that is just like with a planer - use a sacrificial board in front of and behind the work piece.
Now, that's all fine and dandy if you have straight edges on your work piece but if it's oddly shaped or round, then what do you do? Well, what I do is save the cut-offs from the work piece. They're the same thickness and should fit pretty closely to run in front of and behind the target work piece.
A few weeks ago I cut a large Lazy Susan and didn't allow enough on my scrap pieces to use them on the drum sander. What I ended up with was a very beautiful Walnut Lazy Susan but at the correct angle, and if you knew what to look for, you could see some very faint snipe. I didn't take a photo but I could see it.
So when I made this even thicker Walnut cutting board I was determined to not fall into that trap again. My cut-offs were large enough to go in front of and behind the cutting board and what I ended up with is a perfectly flat 18" round surface. I cut the scrap pieces down to where they fit just inside the width of our 19/38 drum sander and made sure to feed them before and after the cutting board on each pass of each grit from 120/150/220.
I've also done this with angled pieces where the leading edge is angled relative to the grain direction and it truly makes a difference.