What makes plastics go yellow, and, can I clean it off?

[Pop Bumper Pete]

Over the Xmas break I have been cleaning a 'Black Rose' I picked up during the year
Once I clean off the grime, the machine should come up a treat
(I think some of the rubbers are the ones the game shipped with ;)  )

Some of the plastics have gone yellow. (and strangely the others have not yellowed at all)
Is there anything I can do about the yellowed plastics?

Pete

[Retropin]

Clean plastics with a soft cloth and mild detergent in water... NEVER use anything else!.
The yellowing im afraid is a reaction of the plastic with natural UV.. theres nothing you can do about it.. all clear plastic products have some sort of reaction to UV light be it yellowing or going whitish and cracking.
Clear plastic is very susceptable to corruption with other products... alcohol based products will turn them a bluey misty colour which cannot be renoved... once done its permanent, so mild detergent and water only and ALWAYS dry with the print on the upside to prevent it sticking to anything underneath ( very easy to lose artwork like this)... same goes for ramps.. steer clear of any alcohol based products!

[Caveoftreasures]

It could also be yellow nicotine from smokers....alot of euro machines come with yellowed plastics due to heavy smoking around the machines.

I find baby bum wipes the best to clean anything and everything and it never lifts artwork but takes anything yukky off very quickly.

[Pop Bumper Pete]

:(

[johnwartjr]

I would agree, seems to be a UV or chemical reaction. Pulled a goodie bag out of a WCS, and the NOS sling plastics in there were yellowed! Never been exposed to much light, but the machine had been exposed to cigarette smoke.

No way to reverse them that I am aware of.

[oldskool1969]

Hearing a lot of good results for ultrasonic cleaners! yet to try myself though

[Slash]

What about flame polishing with a propane torch?  People say that works.  I haven't tried it myself and if I did I would want to practice on something first. 

Anyone here tried it?

[pinnies4me]

What about flame polishing with a propane torch?  People say that works.  I haven't tried it myself and if I did I would want to practice on something first. 

Anyone here tried it?

That's more for clear plastic ramps to remove the ball track etc, wouldn't have an effect on the yellowing (and the plastic and ink would not survive).

[Slash]

What about flame polishing with a propane torch?  People say that works.  I haven't tried it myself and if I did I would want to practice on something first. 

Anyone here tried it?

That's more for clear plastic ramps to remove the ball track etc, wouldn't have an effect on the yellowing (and the plastic and ink would not survive).

My mistake I thought he was referring to yellowing of ramps.  I have never really noticed plastics with artwork on yellowing,  only fading?  I guess smoke damage as someone suggested could do it.

[femto]

I have read posts on another forum where people have used peroxide on the plastic and left it in the sunlight for a day. The results have been quite spectacular from the photos I have seen.










Admin Edit - Non functional link removed

[Olivia_jason]

believe it or not, Avengers, Xmen and LOTR movies were based on the Original stern pinball theme.   
and stern is so great they Named a band after a Stern title, ACDC 

[GORGAR 1]

What about flame polishing with a propane torch?  People say that works.  I haven't tried it myself and if I did I would want to practice on something first. 

Anyone here tried it?

Flaming works great just move around or it will melt. Also dishwasher mine come up great.

Peter

[ajlaird]

I have read posts on another forum where people have used peroxide on the plastic and left it in the sunlight for a day. The results have been quite spectacular from the photos I have seen.

This methodology is well known in vintage computer circles.

Here's a couple of links:

http://eab.abime.net/showthread.php?t=39531
http://www.hardwarezone.com.sg/feature-how-whiten-your-yellowed-plastic-gadgets

UV lamp is not required except for speed; natural sunlight will do the job.

Unfortunately I have no idea if the chemical composition of pinball plastics are similar enough to get the same sort of results.