The loss of sensible and private information is quite an important issue nowadays, especially if we're talking about photos or documents that might seriously affect either the user's personal life or their finances (depending on the nature of the specific information found on the discs). For this reason, it's a very good idea to make sure that nobody can actually read the disc once you've disposed of it, so we've compiled here a list of destructive techniques that will help you throw away of your CDs and DVDs without ever fearing that somebody might simply pick them up from the trash and read them.
First method: Hammer + towel
The first thing you could try is mechanically destroy the disc. While simply bending it is not exactly a very safe solution (the disc could actually brake and send shards flying in every direction), you could do something rather different. Hence, take the disc, bend it slightly, place it inside a towel, in order to prevent shards from flying around, and then “batter it” with the hammer from the opposite direction of the bent area. The disc will most likely break, and then you can simply dispose of the shards by throwing them in the garbage bin.
Second method: Scratch it like you mean it
Probably the most popular method of rendering an optical disc unusable is by seriously scratching it. There are several machines available on the market that will take of this issue for you, and they might be a good choice if you have to dispose of large quantities of CDs or DVDs on a very regular basis. Otherwise, you can simply take an object with a sharp point (a knife, a cutter, even a fork or a nail will get the job done pretty fast) and scratch the disc in all directions, without necessary following any patterns.
Plus, there's a little catch here. You should try to also scratch the surface of the label, not just the rear side. That's because, in general, CD and DVD manufacturers provide an enhanced level of scratch-protection for the backside, while the label is considered to be “thick” enough to provide the necessary level of protection.
Third method: Microwave oven
Here's a simple one. Just take the discs in question (preferably one at a time), place them in the microwave oven, set the appliance at maximum power and 10 seconds functioning time, and then start it up. The data will be completely destroyed, and you'll also benefit from quite a light show (as a bonus). However, you should be careful when opening the oven's door, given the fact that super-heating the CDs will lead to the emission of some pretty dangerous fumes.
Fourth method : Mass destruction with fire OK, so let's say you've got a large number of CDs or DVDs you want to get rid of. It's rather difficult to start scratching them all, or hammering them down. So, if you want to “eliminate” several discs with only one shot, probably the best bet would be to set-up a fire (preferably in a metal can of some sort) and throw them all in. The heat will certainly take care of that pesky data. One word of advice, though. You should make the fire in an open area, since, as mentioned earlier, burning CDs do have a tendency of emanating dangerous fumes.
Of course, fire is a very good solution for one disc as well. All you have to do in this case is take a match or a lighter, light them up, and move the flame on the surface underneath the DVD.
These are only a few ways in which you can make sure that nobody will be able to extract information from the CDs/DVDs you've thrown away. If you have any other ideas/methods, please do let us know about them.