Do gold hot stamps degrade to silver, over time? (2 Viewers)

[upNdown]

I’ve been collecting these Plaza hot stamps. It seems like so far I’ve identified either three different versions or six different versions.
I looked at each chip under a flashlight and most of them seemed pretty clearly either gold or silver. So my observations suggest there are at least 6 different versions of this chip - three with silver hot stamps and three with gold.
But common sense tells me that’s weird, and that it would make sense if the silver and gold chips were all gold, but some had degraded to look silver.
I won’t try to post pictures to illustrate, because cameras do funny thighs in different lighting. But here’s what I have:

 

[grantc54]

I have chips that had a gold cancellation stsmp turn silver after they were washed in a ultrasonic with cleaner.

 

[ekricket]

Not all foils are the same. Some are for different temps, some are for applying to different materials. So even though they look the same they may not be.
So it’s possible that they may have used a cheaper foil with a thin brassy gold layer over a base layer. I’d expect patchy areas though, not a uniform wearing.

 

[upNdown]

Yeah, here’s another pair of chips I received today - images of both sides.
I have no doubt these were stamped with different color foils

 

[moechar]

@JeepologyOffroad

 

[Josh Kifer]

Not all foils are the same. Some are for different temps, some are for applying to different materials. So even though they look the same they may not be.
So it’s possible that they may have used a cheaper foil with a thin brassy gold layer over a base layer. I’d expect patchy areas though, not a uniform wearing.

I'd agree with this assessment.

 

[BGinGA]

Some older gold foils can tarnish with exposure to sun and oils (and some cleaning agents), essentially turning silverish in appearance.

 

[CrazyEddie]

I have some worn starbursts which I got as a single batch (suggesting they may have been produced together) where some were obviously gold but some were apparently silver. So call this another data point in the ".... maybe?" column.

 

[AfterTheFact]

I have also had gold foil turn to silver after a tsp bath…