Easiest and safest way to make cd unreadable?

[alpacino]

Relax, I'm sure "backup copies" of the game can be downloaded with ease

Oh yes, sure! . But what I forgot to mention is that this friend of mine is an exhaustive video-game collector, so just imagine his frustration.

While we are on the subject, does anyone know why some CDs are very transparent-like and you just see through them? Windows DVDs, audio CDs, etc. are somewhat thicker and cannot see through them while blank recordable disks are thinner and transparent. Why is that?

Isn't it because those Windows and audio CDs are pressed? I mean the way they are manufactured, making them thicker and more resistant.

[anon]

Exactly. I'd say it depends on the batch process. Had 3 CDs, same manufacturer, one broke easily, while the other two just bent.

I resumed my cleanup today, and ended up breaking three discs, two Verbatim and one brandless. The first Verbatim (white label) snapped instantly, the other two bent like paper and required pinching and bending on the opposite direction to be broken.

While we are on the subject, does anyone know why some CDs are very transparent-like and you just see through them? Windows DVDs, audio CDs, etc. are somewhat thicker and cannot see through them while blank recordable disks are thinner and transparent. Why is that?

Isn't it because those Windows and audio CDs are pressed? I mean the way they are manufactured, making them thicker and more resistant.

Even blank media aren't all the same in this regard. I guess it depends on the quality and/or thickness of label, reflective layer or both. The worst offenders are virtually transparent when held in front of a light source.

Don't get me started on those very cheap discs which had no label at all, making both sides look the same. I used to put a sticker on the non-recordable side to tell them apart... stickers like "side A", "side B" and numbers from 0 to 9 which came with blank cassettes.

[Master Razor]

Don't get me started on those very cheap discs which had no label at all, making both sides look the same.

i remember those. I used to love them as kid, but I never could tell apart one from the other.

[Master Razor]

I found something interesting that just never occurred to me.
compact disc - Why do CDs and DVDs fill up from the centre outwards? - Super User

Since cd/dvd/blu-ray writers all read from the center of the disk to outwards, why not just scratch the exact starting bit of the disk? If you scratch the filesystem, which always start at that point, wouldn't you render the disk unreadable?

[takomania]

^nope

the data would be unreadable to regular people, but if you're talking about forensics, it's no different to blowing away partition tables on a hard drive - the data is still there, it's just not readily accessible.

[anon]

Since cd/dvd/blu-ray writers all read from the center of the disk to outwards, why not just scratch the exact starting bit of the disk? If you scratch the filesystem, which always start at that point, wouldn't you render the disk unreadable?

The result would be the same as quick-erasing rewritable media: the disc will appear to be empty (or unreadable), but the fact the actual data remains on it and is completely contiguous makes it highly vulnerable to file carving. And if you're picturing some dudes in lab coats working in a clean room, it can actually be done with a pirated copy of WinHex in a few minutes' time.

And who knows, maybe a long ddrescue session would even be able to read the scratched area. Two years ago I managed to completely recover some CDs that looked like they'd been used as knife sharpeners. It took several days, but I got it done.

[takomania]

And who knows, maybe a long ddrescue session would even be able to read the scratched area.

no need (depending on the disc type). forensics can easily separate the layers of the disc and rebuild using new plastics. i don't know if it works with pressed discs, but it definitely works with burnt cds/dvds/gds etc.

you'd have to scratch deep enough to destroy the dye platter on the disc, below the plastic.

[anon]

In other words, breaking them into little pieces remains the most effective way!