Yes you are correct if you are referring to recordable media made using a consumer level cd burner. These use a low power laser to burn pits in the form of dots and dashes (representing 0s and 1s) into a layer of ink. This layer lies just below a reflective layer which in turn lies just below a layer of paint. All of these layers are on TOP (up facing side) of the recordable media. Scratching or sanding the bottom (down facing side) of consumer level recordable media does NOT destroy data. It only makes it difficult for the laser to penetrate the clear plastic to reflect off of the reflective layer and back down onto the data (ink) layer to read the disc. If the scratches are heavy enough the laser can't penetrate at all. If the scratches are light, then the laser might just be refracted causing read errors. Commercial level recordable media, (like the ones you purchase software or music on) use a much higher powered laser which burns the pits into a more robust layer of plastic instead of ink. This makes them less susceptible to damage but also harder to destroy. The government process that is being referred to, is most likely referring to this type of media (I can't say for sure as I've never worked for the government). The reason I say this, is that the recording layer of plastic that a commercial level r media writer burns to is located closer to the midway point inside the disc. It is therefore feasible to grind away at the bottom (down side) of the disc until the data layer is reached and destroyed, while still retaining a thin layer of plastic making up the top protective layer, reflective layer, and label. This process, as described, would not work for consumer level recordable media because tye recording layer is located so close to the surface of the top (up side) layer. That being said, sanding or burning off the TOP (up side) layer of consumer level recordable media, will result in completely destroyed data. Just be sure to remove all of the darker colored material from the top level until all you see is clear plastic material. What you are left with is clear plastic and nothing more.