Unclean UV appearances: factory variable or second hand contamination?

I have two Bolivia 20 Bolivianos notes, both happen to be series I DLR notes (P#239A) but they were purchased at different times from different sellers. Here's our page on it:

20 Bolivianos (Dalence, Series F-J) - Bolivia – Numista

Both notes are UNC and look great under normal light, however both of them have unclean UV appearances.

Here is note 1:

These are the areas I am concerned about, a bright blue fluorescence:

Here is note 2:

These are areas I am concerned about, an odd gold or bronze fluorescence:

I want to know what the most likely source of these marks is. They only appear under UV. Under normal light the notes appear UNC, as advertised.

As a matter of interest, I have a third note of the same kind from a third seller, and that note is perfect under UV and normal light. 

Regarding Note 1., I have seen this on notes which were water-damaged. 

Note 1 might have been exposed to water.

Consider: human sweat from a pocket wallet

gyoschak

Consider: human sweat from a pocket wallet

UGH - yeah 🤮

gyoschak

Consider: human sweat from a pocket wallet

According to Odd Job, both notes are in UNC condition, or unless it has been washed and tumble dried.

They are both UNC, with no signs of any damage under normal light. That's the strange part about this.

odd job

They are both UNC.

 

with sharp original corners?

Yes, nothing at all wrong with the notes, or I would have sent them back.

There was probably a spill of UV ink and/or someone at the factory with dirty gloves (ink/pigments) handling still not completely dry the stacks of notes.

The other thing I was thinking of is contamination from another note. The bronze/gold marks on note 2 are odd, they aren't a colour that is on the note, not a UV ink anyway.

Is it possible there were two notes stored together in a sleeve and the UV ink on one has rubbed onto the other?

By the way, another question: do these unclean UV appearances now render the notes not UNC?

Have you ever wondered why the contaminants are only around the edges top and bottom, and the left hand side corner only? Is it possible that this note was once handled with dirty hands?

I do not examine my banknotes under UV lights, and therefore in my own little world, the grading of notes is all done with my naked eyes.😄

That's the interesting part: your notes could look the same under UV. Until you check, you don't know!

I don't think these are from handling. They don't look like finger marks to me.

It is interesting all the same, what UV reveals on our UNC notes!

But still does not explain why all these 'stains' are only concentrated in areas that are normally handled with bare hands. If you find them all over the note, I would understand.

Here's another one, the note is UNC, I can find no defect under normal light:

Under UV, both sides of the note have a contaminant that makes bright blue marks:

One thing I just proved is that the UV ink can easily rub off one note and go onto another note.

I ordered a bunch of Peru notes off ebay and there was a blue fluorescence on one note that shouldn't be there. When I checked the adjoining note it had a bright blue fluorescence in the exact same area as what was seen on the first note.

That's quite concerning, because  the majority of sellers will put the notes all together in one pouch. And I think this is the cause of the type of contamination seen in some of the pictures where you have fluorescence of an unexpected colour on a note.

Another example of an unknown contaminant:

I returned the note for a refund. The seller then checked that note very carefully and advised me that the contaminant was visible under white light also. I didn't notice it, but I didn't check in serious detail.

The interesting thing about this case is that the seller has other notes in a bundle and they are all contaminated in the lower right corner.

Another example, from a different eBay seller. It is a test note, the Goznak 100 years printer anniversary. Looks okay under white light but is contaminated as evidenced under UV:

It was bought as one of a pair, because there are two different versions of this note. Luckily the one that is contaminated is one that I already have a clean example of:

The sellers attitude is that the note is from a bundle and they are all like that. That is his position without checking them under UV.

It's a shame because I have bought a fair amount of notes from him before and now I am not that keen.