OT: Gold aluminum plus isopropyl alcohol equals purple color?

https://www.flickr.com/photos/27532210@N04/?
I don't know what that is, so I don't know whether anybody here has any idea
what it is.
Purina Fancy feast cat food cans, the top is gold colored aluminum. I usually wipe the inside corner with a few drops of isopropyl rubbing alcohol.
The paper towel always turns out pinkish, purpleish. What is that? It does NOT come from the label. The label is nowhere near the wiped area.
Some sort of coating on the aluminum seems strange, but I cannot imagine what else would discolor the paper towel. A reaction between the aluminum and isopropyl alcohol seems like a remote possibility, but I really have no idea.
The gold color is made with paint?
Thanks.
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7/22/21, 6:40 AM, John Doe writes:

You can try to clean the color off with alcohol.
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A nym-shifting deranged troll... see also...
and others...
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Corvid < snipped-for-privacy@ckbirds.net> wrote:

> Path: eternal-september.org!reader02.eternal-september.org!aioe.org!xUOiStaTX9GQDNXPji0+sg.user.46.165.242.75.POSTED!not-for-mail
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On 7/22/2021 1:45 PM, John Doe wrote:

Why go ad hominid when his reply was relevant to your question? You're the one being a troll.
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An idiot sticking up for a nym-shifting troll, acting like it can't read...
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Bob Engelhardt < snipped-for-privacy@comcast.net> wrote:

> Path: eternal-september.org!reader02.eternal-september.org!news.uzoreto.com!newsfeed.xs4all.nl!newsfeed7.news.xs4all.nl!news-out.netnews.com!news.alt.net!fdc3.netnews.com!peer03.ams1!peer.ams1.xlned.com!news.xlned.com!peer02.iad!feed-me.highwinds-media.com!news.highwinds-media.com!spln!extra.newsguy.com!newsp.newsguy.com!news1
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7/23/21, 1:01 PM, John Doe writes:

A nym-shifting troll seeks help trolling YouTube, after Google shuts him down.
Subject: OT: Easiest way to make new anonymous YouTube accounts? http://al.howardknight.net/?ID 0878195400
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"... but posting under YouTube videos is fun"

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My replies to this nym-shifting troll show up plain as day on Internet websites that mirror USENET... :D
see also...
and others...
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Corvid < snipped-for-privacy@ckbirds.net> wrote:

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