I usually use scanned copies of documents to transport them, save them, and enlarge them. I don't often have cause to do much more. However recently, I received a copy of a letter where only the front had been copied. The letter had been folded in thirds with something being written on the back. Luckily it bled through. Scanning it, rotating it, and flipping it horizonally made it easy to read.
A mirror would have worked or I could have held it up to the light, but this was much easier. Here is a blog post showing both images and how it worked.