Partially discoloured part

[brickmack]

So, a few months ago I got a big bag of random parts from eBay, and only a few weeks ago I got to start looking through it. Except for being a bit dirty, all of the pats were in good condition, except for one part. A single 1x2 light blue tile was discoloured, but in a very strange way that I haven't seen before: only the short ends were yellowed. The rest of the part was it's normal light blue colour, nearly indistinguishable from any other of the same type. All of the parts were disassembled so I couldn't be sure if it's from touching another part, but I haven't seen any colour issues on any other parts in the bag. Any ideas what could have caused this? (Unfortunately my camera isn't working at the moment, so I can't supply pictures, sorry)

[jmupton2000]

Seems to have been a problem with certain batches of mid to late 1980's blue bricks from my experience, for example I have this old thing just lying on my desk at the moment:

It was left in direct sunlight for a number of years and the exposed part of the brick, the two studs on the far right have now faded with a definite yellowy hue. (It is also mucky as well I admit, didn't seem any point cleaning it really!) I also have a couple of 1x2 and 1x4 tiles that were part of the same model where only the ends were exposed to the light and the end faces have gone the same way. Now all consigned to the scrap skip at the back of the Lego City builders merchants!!

Edited August 29, 2011 by jmupton2000

[1980-Something-Space-Guy]

So, a few months ago I got a big bag of random parts from eBay, and only a few weeks ago I got to start looking through it. Except for being a bit dirty, all of the pats were in good condition, except for one part. A single 1x2 light blue tile was discoloured, but in a very strange way that I haven't seen before: only the short ends were yellowed. The rest of the part was it's normal light blue colour, nearly indistinguishable from any other of the same type. All of the parts were disassembled so I couldn't be sure if it's from touching another part, but I haven't seen any colour issues on any other parts in the bag. Any ideas what could have caused this? (Unfortunately my camera isn't working at the moment, so I can't supply pictures, sorry)

Often, if a model is assembled in some way that exposes only a few areas of a part, and it is exposed to the sun, that area will get discoloured. I have seen this with a few used sets I own that are slightly discolored. Disassemble the set and you will have an ugly multicolor part. I find UV discoloring to be Lego's Achilles' heel.