Disc scratch

A disc scratch is a shallow crack on an optical disc, which affects the quality of the usage of the disc. Scratches show up as discolored lines on a disc, usually white lines.

Details
Due to the restrictions of ROM chips, disc-based media was preferred for the last three generations of consoles. Spinning media of any kind (discs and mechanical hard drives) is actually technologically inferior to solid state storage (in terms of access speed, size, complexity and power consumption of the access device, and robustness, as ROM chips and flash memory have no moving parts): the era of CD and DVD storage occurred largely because a stack of ROM chips that matched the capacity of a compact disc or DVD would be both extremely large and prohibitively expensive (when the PS1 came out, RAM chips cost about $35 per megabyte, while a 700-megabyte CD cost about a dollar to make), though with the rise of cheap, compact flash memory this is gradually becoming less of an issue.

Unfortunately, discs are infamous for getting scratched. Game consoles have a harder time reading scratched discs because the scratches prevent the lens from reading the data printed onto the disc. As the disc gets more scratched the game will become less functional until it can't be played anymore.

Discs are very fragile and can get scratched easily, and while it usually happens more often to younger and careless gamers, even the most cared and protected discs can get a few scratches because even the game console itself can accidentally scratch a disc while reading it.

It is possible to fix a scratched disc. However, it can be very difficult, and the slightest mistake while doing so can end up damaging the disc further, so be extra careful when doing so.

One of the infamous technical issues of the Xbox 360 is that when the console is moved the disc inside of the DVD tray suddenly gets a circular scratch on it, making it impossible to read the game data. Some people claim that this even happens randomly without moving the console. This resulted in Microsoft adding a warning label to newer models of the Xbox 360 and Xbox One to NOT move the console while a disc is inside.

How scratches affect games

 * 1) Loading screens become longer. Sometimes the game can even freeze during a loading screen which in turn could corrupt data.
 * 2) Sometimes the game will fail to boot up.
 * 3) The console will start making louder noises due to needing to put extra effort to read the disc. Over time the console's lens starts wearing down from having to put more effort than usual to read scratched discs, which reduces its ability to read any disc.
 * 4) The game can crash or slowdown significantly. On most occassions, it will freeze.
 * 5) Because the lens has a harder time reading the data on the disc correctly, glitches and bugs can occur, Like graphical glitches.
 * 6) Parts of the game can become outright unplayable because the scratches make the section of the disc completely unreadable.
 * 7) Some games skyboxes become trippy (example: Battle for Bikini Bottom, Xbox version).
 * 8) If playing on the PS4, the message "DISC IS NOT RECOGNIZED" may appear.

Prevention

 * 1) Always keep your discs in their cases when not in use and keep those cases in a safe place where they'll be unlikely to fall over and get damaged.
 * 2) When you're done playing don't leave the disc in the console's tray, put it back inside its case.
 * 3) Never touch the disc's surface. When handling the disc, make sure your fingers don't accidentally touch the surface either.
 * 4) Avoid long play sessions; it'll reduce the chance of your console scratching the disc. If you do plan a long play session, maybe play multiple games for a short time each so the discs don't run for that long.
 * 5) Always check for dust or any form of litter on the disc's case or worse on the disc tray in the console before placing the disc into the console.
 * 6) Carefully place the disc on the console and make sure it's properly placed.
 * 7) Use a microfiber cloth and avoid paper products when cleaning a disc; paper products can leave litter behind. When cleaning a disc, wipe from the inside spoke to the outer edge; NEVER wipe in a circular motion, as this can rub scratches deeper into the disc.
 * 8) When cleaning a disc, use distilled water; tap or drinking water can leave mineral stains behind. If distilled water alone is insufficient, use isopropyl alcohol, preferably as high of a concentration as possible. Only use a damp (not dripping wet) cloth to clean a disc; do not completely submerge a disc in any liquid.
 * 9) Clean microfiber cloths regularly.
 * 10) If a disc gets wet, dry it before use or storage by wiping the disc with a dry cloth and letting it air dry for at least two minutes.
 * 11) Don't move your console while it's reading a disc (for example tilting it). This will likely create a circular scratch due to a phenomenon called a read head crash where the read assembly touches the surface of the disc and scores a scratch in it like a lathe; this can also occur on a mechanical hard drive, though it is rarer. The Xbox 360 was particularly infamous for these scratches. That's why the Xbox One had the message "Do not move the console without first removing any disc inside."
 * 12) NEVER put a disc on top of another disc in the disc player.
 * 13) Be careful when lending your game to someone else as that person might not treat the disc nicely.
 * 14) If you buy a game used from a store, make sure you check the disc for scratches before taking it. If possible ask the store clerk if they can test the game to check if it still works. Also always keep your warranty in hand just in case especially if you buy used games online because you can't test those before buying them.
 * 15) *If you're buying an Xbox 360, PlayStation 4 or 5 game on disc, ask the owner to try to re-install the data on the disc to the internal hard drive. If it doesn't fully install that means that the game will not be fully playable as all of the game data on the disc has to be read to correctly in order to install the game on the hard drive. Same as delisted Xbox One and Series X games as no longer eligible to download them.
 * 16) * Xbox One and Series X use the game disc's inner ring as a "key" disc (or a Play Disc in 2-disc games), allow players to finish installing the game via the network by searching the game's title on the Xbox Store (as long the game is currently listed), and select "INSTALL: You can play this" option. Another option is to use an Xbox mobile app when the game installs from the network while keeping the game disc inside the console.
 * 17) ** Because installing Xbox Original and Xbox 360 backward compatible game discs requires an internet connection on your Xbox One and Series X, there is the notice when you have to use the "Install" option to download them to the system.
 * 18) Check your console for any hardware or manufacturing errors that might cause the system to scratch discs.
 * 19) If the disc has a crack on it, (especially on the data layer) or if a chunk of the disc is missing, discard it. You should never use a disc with any cracks on it.
 * 20) While signal surface scratches can be repaired, if the disc has a scratch on the label side (i.e., light shines through the disc if you hold it up to a light source), it is permanently damaged.
 * 21) If your disc isn't scratched too bad, you can buy a disc scratch removal machine or kit. Some stores may be able to unscratch your disc for a small fee.
 * 22) Since the PlayStation 3, Sony's home consoles have used the Blu-ray disc format for games, which are a lot more scratch resistant. Microsoft has also used this format since the Xbox One. However, even with the extra scratch resistance, it's still a good idea to handle your discs properly.

How to get rid of disc scratches
'''NOTE: Make sure your disc is 100% damaged before doing this. If it's not damaged, doing this will cause permanent damage.''' And there you go! Your disc should now be able to work again.
 * 1) Take your disc and apply it to some water to get all the smudges off. NEVER do it in a circular motion.
 * 2) Squirt out a small ounce of toothpaste. Make sure the toothpaste doesn't have any tiny beads on it (If it’s hard to tell, then look on the ingredients box for polyethylene. If that’s there then your toothpaste has beads). Once it's on the disc, start spreading the toothpaste around the disc. If the disc has heavier scratches you may need more toothpaste.
 * 3) Once your finished applying the toothpaste to the disc, leave the disc on a surface for a couple of minutes.
 * 4) When coming back to the disc, use your fingers to rub the toothpaste off the disc. It may take longer due to the fact the toothpaste has hardened.
 * 5) After you have removed the toothpaste, get a cloth and make the disc dry.
 * 6) When your disc has dryed, get some white stick deodorant and apply it across the disc.
 * 7) After you have applied the white stick deodorant, let it dry for a couple of minutes.
 * 8) After it has dried, put it under some water and apply water to your disc.
 * 9) Once you are finished with it, wipe the disc with a cloth.