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Removing Sun-Yellowing on a UN Lapel Pin

Article about: I have an old UN pin that's been sun-stained, turning the UN blue to a dirty teal color. It is brass with a clear enamel coating. You can see the original color that's painted on a tip of th

  1. #1

    Default Removing Sun-Yellowing on a UN Lapel Pin

    I have an old UN pin that's been sun-stained, turning the UN blue to a dirty teal color. It is brass with a clear enamel coating. You can see the original color that's painted on a tip of the flag. I would like to remove the yellow staining and return it to it's original color.

    How should I go about this without damaging the pin?

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    It should looks like this color.
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    *Pics aren't the greatest, but I don't think it needs to be scrutinized at 50x to check the maker's mark for authenticity *

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  3. #2

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    Could be wrong but I think it's permanently damaged by the sun

  4. #3

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    Australia is correct, sun bleaching is permanent because UV rays absorb colour.

  5. #4
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    I wouldnt think that yellowing could be removed either....

    Further more, the yellowing is part of the process.
    Its patina honorably earned over time - why not leave it as is.

  6. #5

    Default

    I've read that the staining isn't necessarily permenant (though not in all cases).

    "It turns out this yellowing is usually the result of bromine released from flame retardants added in the master batch to facilitate production and later molding. (Bromine, you will recall is a dark reddish brown liquid at room temperature) The loss of bromine doesn't necessarily mean that the plastic itself is deteriorated or unable to give decades of further performance, though a mental illusion often convinces us they feel brittle or rough.

    Though the key chemicals are often used as bleaches and cleaners, the process is not bleaching the plastic or removing dirt. It's just mobilizing the bromine, which has migrated to the surface, and forms a stable complex with atmospheric oxygen.

    The second key point is that ultraviolet light is CRITICAL to the process. The UV is what actually mobilizes the bromine -- just as heat and UV often contribute strongly to plastic yellowing, but mobilizing the bromine to the surface in the first place. If you use the solution alone, you may not get appreciable effect from soaking plastics for weeks in you basement. Since you only need a day or so of direct sun (or the equivalent in UV lamp or indirect shaded sun), you won't damage the plastic"


    -Paraphrased from here: De-Yellowing plastic - the stain isn't permanent after all - Creators Corner - Ex Isle Forums

    Other websites, such as "ehow," yield similar information. It seems rather a hassle, and was wondering what the easiest solution would be.

    I am going to wear it with the tie behind it for a presentation; though I may just leave it as it is.

  7. #6
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    Default

    I as well feel in this particular case that the damage has been done and it is irreversible and any attempt to take out the yellowing will damage the finish on the pin what has happened here is a very natural aging process and as said by others it is now part of the patina.
    I think you would be better off trying to find a different example and keep this as a filler till one comes along.

    Regards Mark
    Always on the look out for WW II Canadian Helmets and Cam nets to add to my collection.

    Found a Canadian Mk II Medics Helmet and yes I know they are about as rare as hens teeth !!!!!

  8. #7
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    Hey, I think it looks good as it is, shows it has been worn!!

    Dean

  9. #8

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    Alright then, thanks for the input!

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