What causes the weird stains on Japanese SFC and GB carts?

[SuperDerpBro]

It's almost always on the back of carts. Unlike the normal yellowing we see in North America its always super uneven. Not saying it can't be uneven here.. Its just crazy uneven over there.

Is it the same as SNES console yellowing? Or is it like a stain that can be removed? To me it almost looks like its been cleaned with a hard chemical or stains from smoking heh.

example the back of this cart http://www.ebay.com/itm/d3048-MARIO-LAND-2-GameBoy-Nintendo-Japan-/351541290110

Wish i could tell if it would be removable or not. heh. A high percentage of the gameboy carts i want are like this.

[Protoman]

It sure is annoying. One fix is to take another game and open it and switch the backs. But a way to clean it off, I don't know. And if it's due to smoke damage or sun bleaching or something, not sure.

[VegaVegas]

http://www.retrofixes.com/2013/10/how-to-clean-whiten-yellowed-plastics.html

Apparently it is reversable with some sort of hydrogen peroxide 12% that can whiten the plastic or in other words, reverse the efffect. I've never tried it so far but I think I'll try to whiten some cart today because the weather is sunny today

[jensma]

I used this composition last year on my yellowed SNES: https://en.wikipedia.org/wiki/Retr0bright

It worked perfectly!

[FamiGamer86]

I have heard that Retr0bright won't completely de-yellow plastic, and sometimes, it will re-yellow fast.

[L___E___T]

 

The yellowing comes from inside the plastic itself.  It's flame retardant chemicals that cause it.  A slight deviation in the amount required either way makes a big difference to the effect over time, hence why different molds have different extent and even sometimes on the same piece of plastic itself, will stain/fade much more than usual.  Because it's an invisible chemical they just add to the plastic for legality, it's not something you'd notice on the production line.  More here: http://www.howtogeek.com/196687/ask-htg-why-do-old-computers-and-game-consoles-turn-yellow/


TL:DR - it's accelerated by sunlight, heat and time.  You can retrobrite to get rid of most of it, but there's no perfect solution really.

[famifan]

It's almost always on the back of carts. Unlike the normal yellowing we see in North America its always super uneven. Not saying it can't be uneven here.. Its just crazy uneven over there.

just imagine a heap of carts exposed to sunlight :-)

the carts could be exposed to sunlight only partially. Thus the yellowing pattern could be so unpredictable.

[SuperDerpBro]

It's almost always on the back of carts. Unlike the normal yellowing we see in North America its always super uneven. Not saying it can't be uneven here.. Its just crazy uneven over there.

just imagine a heap of carts exposed to sunlight :-)

the carts could be exposed to sunlight only partially. Thus the yellowing pattern could be so unpredictable.

But almost always on the back of carts? hehe

http://nintendoage.com/forum/messageview.cfm?catid=7&threadid=153956

[L___E___T]

 


As it says in the linked writeup - this is because there are more back halves made than front halves, as they're usually pretty uniform in design.  

So an over index of the chemical in those will make hundreds of thousands have the same staining potentially.  

Tobacco will of course also stain, but this effect is not from tobacco it is a naturally occurring effect that is exacerbated by UV, heat and other exposure.  

You can retrobright it away, but it's inherent to the plastic so that's always a treatment, rather than a cure.

[Pikkon]

I tried to retrobright the back on of super famicom game(it was nasty)and it didn't turn out to well.

[chowder]

I've not had much luck with Retrobright or peroxide myself, perhaps due to the lack of sunlight around here

I just buy non-yellow consoles and replace the backs of affected carts.  I think if you get one that hasn't yellowed yet, it's probably going to be alright for the foreseeable future.