Via a completely nerdily pointless article on BoingBoing about cha-cha and mambo songs that there are a surplus of anyway. This is the addendum, when it should have been the WHOLE POINT.
A reader comments:
Here are a couple of techniques I've used when dealing with warped vinyl. In all cases I've done it so I could get one good copy, which I would use in the future (ie. I didn't use these techniques to play the vinyl every time). Also note, I probably wouldn't recommend these techniques with a really expensive turntable and stylus, though they never messed up mine.
1. Try weighting down the stylus with one or two pennies. Or perhaps a nickel (which weighs about 5 grams).
2. Place the vinyl onto a hard surface (eg. table top), between two sheets of clean paper (not the sleeve, since it sometimes has stickyness), and then place a heavy, flat weight on top for 15 minutes or so (I'd use an unabridged dictionary). While the vinyl usually has enough physical memory that it'll ultimately re-warp, it's possible to flatten things out long enough to record one copy.
3. Drizzle a bunch of distilled water all over the surface of the vinyl (avoiding the label). While I usually used this to reduce pops and clicks from scratches, the added dampening from the water would sometimes be enough to hold the needle in the groove on warped records.
4. Lastly, play it at a lower speed, so the needle doesn't jump, then process the recording to shorten the time and raise the pitch. While I did this a couple of times, it was back in the early 80's before I had a digital processor, so restoring the sound in the end wasn't so easy, though I could get close.
He doesn't mention one that worked on my original copy of Let It Be: Leave the damn thing on a flat surface under a piece of glass in front of a window for one day. Simple.
raincoaster 
I don’t try to flatten my records unless I don’t value them very much. I just play them on my 70’s vintage ‘Transcriptors’ Irish made turntable (one of the best made at the time – side note – showed up in a scene in ‘A Clockwork Orange’ as it looked so futuristic). What sold me the turntable in the first place was the stereo store guy playing a record with a serious warp – you could not hear it at all! The tone arm does not move vertically at all, just the cartridge, allowing very low tracking weight, and more importantly low tracking MASS. That is, to get a low tracking weight with a conventional tone arm (thus low record wear, and better sound reproduction) you have to hang a big wieght at the far end of the tone arm, thus doubling the mass of the tone arm. When it hits a warp or scratch, the tone arm is launched off the record like a skier hitting a bump on the hill. With the low mass Transcriptors system, the cartridge follows the bump or scratch up and down with minimal distortion of the sound. I have played records with serious scratches which result in only a tiny ‘ click’ as the stylus hits them.
As for weighting your stylus down with pennies – YIKES – that stylus is just going to drag it’s way down the grooves, planing the top off of them as it goes along. Remember, the records are soft PLASTIC, and the stylus is a hard GEMSTONE.
Please…for the love of GOD….dont’ go drizzling water and putting pennies on your stylus…. The net is full of GOOD ideas for reducing warps in records… The one to use a sheet of glass and put in the sun is a decent one. I’ve also seen one using two sheets of glass and an oven on warm…and then just let it all cool off naturally and you can have a reasonably flat record back….
Thanks for the advice. Water and electrical appliances should never mix…except in the houses of people I really don’t care for!
I have used ovens, metal bowls, and old LPs to make very cute little planters, so if all else fails you can start a garden with your warplings.
If all else fails…
http://backseatkiss.com/recordbowls.html
“Firewood carrier” eh? I never thought of that…surely there’s a copy of “Burnin’ Down the House” just waiting for this treatment.
In related news, some of those old 78’s refuse to bend, although they do become nice and ruffle-y.
Pro-Ject Audio Systems turntables have a clamp in the center that immobilizes warped vinyl. Never, never, never, never NEVER put weights on the cartridge. Use an approved cleaner and fluid like the DiscWasher.
I remember hearing about an optical device that essentially scanned the grooves and translated that into digital, but it was at least ten years ago and outrageously expensive.