I've always felt that there was never enough light to illuminate all those little corners and dark shelves of any gunsafe I've owned, and the safe lights I've tried before were never quite up to the job. But I'm happy to say that annoying problem is now over.
In the camping section of a local department store, I found the Coleman Accessory Light (product number 830-250HD). This light mounts magnetically, operates off of four AA batteries, and can be attach to the steel interior ceiling of any gunsafe instantly, and in any position. It comes with a mounting template, plus a steel mounting bracket so that the light that can be attached to a non-magnetic surface, such as the bottom of a shelf. The mounting magnets on the light itself are extremely powerful, and there is virtually no chance of the light becoming inadvertently detached until you decide to remove it to change batteries, or change its position.
One heck of a versatile, high-quality unit, and inexpensive to boot. I might just add a couple more in different areas of my safe.