[HELP!?] Cleaning more-than-stubborn stains off PBT?

[NexVestrum]

My poor keys picked up some nasty stains a while ago and I had some time today so I tried cleaning them off. They're PBT with paint filled engraving, I used warm water, 3 denture tabs, let them soak for 15 minutes, then rinsed them off annnnnd


_{It looks a lot worse in person.}

ew.

The bottom key is one that was pretty clean before hand, the middle picked up a lot of black around the top edges and looks overall discolored. and the top (and many others) picked up black exclusively around where the paint is. I'm starting to think this black came off of my carrying case, a Grifiti Chiton sleeve. My dishsoap has bleach in it so I'm hesitant to use that, does anyone know if bleach is safe on colored PBT w/ paint? Or does anyone have some sort of magic potion that will make these look like new?

[fohat.digs]

I have never used denture chemicals, that seems weird to me. I use a teaspoon of powdered laundry detergent (Charlie's) with half a teaspoon of Oxi- in a liter of hot water for 10-20 minutes, then rinse well and air dry.

For the 2% of caps that do not come completely clean with that, my next step is a light scrub with a toothbrush and a slurry of wet detergent with or without Oxi-

Next is the foam "eraser" pad and finally I go to my drawing table and use my electric eraser with mildly abrasive white or green strip.

Harsher chemicals like acetone or naptha are great solvents for certain things like adhesives, but would probably play hell with painted legends. Test first!

[SpAmRaY]

electric eraser

How have I went my entire life not knowing such a thing existed.

[fohat.digs]

How have I went my entire life not knowing such a thing existed.

Because people mostly stopped drawing with pencil and paper by the early-mid-1990s.

http://www.ebay.com/itm/VINTAGE-BRUNING-ELECTRIC-ERASER-ERASING-DRAFTING-TOOL-87-201-30W-/221699147340?pt=LH_DefaultDomain_0&hash=item339e4c864c

[Huxley2500]

Try magic eraser.

[SpAmRaY]

Try magic eraser.

You might end up with messing up the texture of the caps with one of those.

[fohat.digs]

Any form of abrasion will scrub the texture off very quickly.

[NexVestrum]

I actually have a new magic eraser lying around and it seems soft enough to not wear down the surface texture. I'll give that a try,  thanks! If that does nothing I'll have to go pick up some detergent and oxi. Thanks for the suggestion, I'll post the results later.

[fohat.digs]

I actually have a new magic eraser lying around and it seems soft enough to not wear down the surface texture. 

Don't be fooled.

Those white "magic erasers" have "stealth" abrasion and will take the texture off quickly.

[NexVestrum]

I actually have a new magic eraser lying around and it seems soft enough to not wear down the surface texture. 

Don't be fooled.

Those white "magic erasers" have "stealth" abrasion and will take the texture off quickly.

Oh thanks, glad I didn't try it yet. These caps would not be easy to replace. So any other ideas?

[fohat.digs]

It looks like that white line art is peeling up already, so I can hardly imagine anything that would not bother it beyond soap and water.

Starting with a toothbrush and a slurry of powdered laundry detergent is almost always safe.

I have never had a problem with alcohol but several people here seem scared of it.

Acetone (and, always test first, naptha) are last resorts for PBT, not ABS, and are almost certain to damage any sort of paint or film or sticker. Likewise for "citrus oil" cleaners.

If none of the solvents will do the job, then you will need to abrade the surface to erode the dirt. If it is a stain that has penetrated the surface, you will have to grind deep enough to get below it.

If you knew the origin, you could tailor a remedy to that, directly, without having to employ the scattergun approach.

[NexVestrum]

Tried warm water/detergent (arm and hammer + oxyclean) - nothing even after scrubbing with a toothbrush. I went fo rthe magic eraser and tested it on the back and side of the cap where and unintentional "polishing" wouldnt be noticable, again, nothing. This stain is EVIL and I'm really starting the think the Grifiti sleeve rubbed some black dye on my pretty caps 

[berserkfan]

How have I went my entire life not knowing such a thing existed.

Because people mostly stopped drawing with pencil and paper by the early-mid-1990s.

http://www.ebay.com/itm/VINTAGE-BRUNING-ELECTRIC-ERASER-ERASING-DRAFTING-TOOL-87-201-30W-/221699147340?pt=LH_DefaultDomain_0&hash=item339e4c864c

You know you yourself are a vintage when the things you use start being listed in the vintage category...

[fohat.digs]

You know you yourself are a vintage when

Harry Truman was president when I was born, Dwight Eisenhower had not yet even been nominated to run for the office of president.

However, I am still a "spring chicken" because I was born in the 2nd half of the 20th century.

There are still at least 5 people still alive verified born in the 1800s.

PS - I own one of those identical Brunings in just about the same condition. My roommate and I were working for Georgia Power Company in 1977 (it was old then) and he swiped it from them. Later, I nicked it from him.