I learned an interesting lesson recently. I had read a while back about some guy who left his Shimano chain in Simple Green for a while and later had it fail quite spectacularly on him while riding. "Who does that?" I thought to myself. Then I go and leave my own chain (actually two of them) soaking in mineral spirits while I use a third in a chain rotation.
Pictured below is how I found the quick link, luckily something obvious enough to be noticed prior to putting the chain back on my bike. Several links of the chain also showed the same damage.
Here's a link to the full 12 MP image for more detailed scrutiny: http://home.comcast.net/~joejackson9..._1303_full.jpg
The most annoying thing about all of this is that my cassette is so worn after 12,000 miles that a new chain skips on it. Since the other two chains in my rotation are done for I'm stuck using the same chain and squeezing out whatever life is left in my cassette. Not really a big deal but not how I envisioned the death of my cassette. I wanted more mileage! I'll probably still get 16k which isn't too bad. And I know to leave my chains in oil from here on out.
 This was the type of mineral spirits in which the chains spent the most time soaking: http://www.homedepot.com/buy/paint/c...its-54685.html 
And just for fun, a picture of my cracked American Classic front disc hub:
And a full size version: http://home.comcast.net/~joejackson9..._1301_full.jpg