Warping can most easily be prevented by storing your records properly. You should never lay vinyl records horizontally. This can lead to bowing of the record as gravity acts on the outside, but not on the inside, which is supported by the label. Store them vertically, on the edge of the sleeve.

Keep your records out of the heat. Heating and cooling cause expansion and contraction, and if the heating or cooling is uneven, your record will have bumps instead of grooves! This means keeping them away from the inside of your parked car if it's sunny. Note: shrink-wrapped records are frequently warped upon purchase. Records from much of Europe typically aren't shrink-wrapped.

I'll admit it, i'm a vinyl junkie. I'll drive over 2 hours to hunt through box after box a records. I like the graphics, the weight, and more importantly the sound. I'm a big buyer of used vinyl (naturally), and there's nothing worse than finding that one album then finding out it's ruined because the previous owner failed to take care of it.

Although this seems like a bit of a strong correlation, records are something like pets or children. They require constant attention and care if you want to enjoy them fully. So, for the good of everyone I present a nice guide to mantaining and caring for vinyl.

The Equipment

1. Cleaning the stylus: You can use a small brush to gently get the collected dust off of the tip of the stylus. If your stylus is all metal, you can wet the brush in isopropyl alchohol to get it extra-clean. However, if you're using a diamond stylus (good for you!), never use isopropyl alchohol to clean it. The alchohol can quickly degrade the bond of the diamond to the stylus.
2. Cleaning the mat: If you're using a rubber mat, you can simply wipe it with an anti-static cloth, or a slighlty damp cloth. If you use a damp cloth, make sure it's dry before putting it back on the turntable. However, if you're using a felt mat, you musn't get it wet. To clean a felt mat, you'll have to use the brush attachment on a vacuum cleaner.
3. The dust cover: Keeping the dust cover up or down is a personal preference. The dust cover changes the sound of the record slightly, and you should decide which one you like. However, if you choose to keep it up be prepared to clean your records and turntable much more often.

Cleaning the Records

1. Cleaning the surface: The actual surface of a record should be cleaned fairly often to maintain good sound quality. You can find kits to do it, but it's just as easy doing it yourself. First, make a mixture of 85% water and 15% isopropyl alchohol. Now wet a a very soft cloth and wipe the record in a circular motion going from the center to the edge, then pat it dry with an anti-static cloth. However, if you're cleaning a 78, never use alchohol, as it will dissolve the shellac. Instead use water with a small amount of dishwashing liquid to clean. Then, rinse with plain water and allow to dry.
2. Cleaning the Cover: This can be difficult and may possible damage the cover even more, so proceed at your own risk. If it's a matte cover, your generally out of luck. It is possible to remove a price tag with a little lighter fluid, but this doesn't always work. Don't try to pick the price tag off. This may work sometimes, but more often you take a piece of the cover with it. The best thing to do is to go to wherever you bought the record from, and begin hitting people in the head for ruining a perfectly good record. However, if it is a glossy cover, there is some chance of restoring it. Hair spray can remove pen marks, and a damp towel can remove general grime, while lighter fluid or a hair dryer make it easy to remove stickers and labels. Again, I don't recommend doing any of this, as it can do more harm than good. You've been warned.

Handling and Storage

1. Handling records: Always, always handle records only on the edges or the label. The less you touch a record, the better. Don't leave records laying about, once your done playing it please put it back in the sleeve.
2. Storing records: First, don't stack your records. Stacking records will lead to warping and sound degradation. Records should be stored vertically, like on a bookshelf. Second, make sure to keep them in a cool, dry place. Otherwise the heat will warp the records, and the humidity will help mold grow. Finally, make sure the temperature doesn't fluctuate to much.
3. Weight: Also keep in mind that records are heavy. One foot of records weighs about 40 pounds. Make sure whatever shelf or surface you're storing your records on can handle the weight.

Restoration

1. Warped discs: Proceed at your own risk. Un-warping a record is dangerous, and very hit-and-miss. Attempting this may further ruin the record.
   
   The two things you need are heat and pressure. One method is two place the record between two pieces of glass, then put it in the oven at 150 degrees F. Keep a close eye on it, and pull it out whenever you think it "looks right". If it's a hot day, you can also place the glass outside. Also, if you can find two pieces of clean, non-stick, and smooth metal you can place the record between them and iron at a low setting.
   
   Again, I wouldn't suggest doing this, but if you want to experiment feel free. Just don't expect it to work all the time. There are attachments to put on your turntable to force a record to flatten, but they put quite a bit of stress on your turntable and may damage it. Also, some very high-end turntables contain an air pump that sucks the record flat onto the platter. However, this can't fixed most warped records, and is very expensive.

Using just basic care of your records will increase their lifespan and their value. If you're not that worried about your vinyl, then please do it for me. Because one day, I just might buy it.