White/Grey residue on PCE/DUO controller d-pads

[tjsnh]

Ok, oddball question - I don't know if I'm the only one who has this problem.

I have a US "TG-16 turbopad" and two JP PC-engine controllers (a white, and a gray).

Both of the JP controllers, but not the US one, have a white powder-like residue on the D-pads. I can't seem to find a way to clean it off. I've soaked the d-pads in water, rubbing alcohol, peroxide, nothing seems to work. The only method I've found is using a fine point needle or dental pick to chisel the residue out of the plastic's texture, but I don't have anywhere near the patience for that.

Has anyone else run into this?

Anyone have advice on how to clean this residue out?

[turboswimbz]

can you upload a photo?  I can't say I've ever quite heard or seen this.  I am intrigued.

[tjsnh]

I'm not at home at the moment, but the picture in this ebay listing shows what I am talking about - check out the D-Pad on the bottom-left controller compared to the others

https://www.ebay.com/itm/NEC-PC-Engine-Controller-Set-Core-Grafx-II-4pc-Japan-Import/232458653040?hash=item361f9d8d70:g:tFMAAOSwXwBZm-JD

Here is one where its just starting
http://www.ukvac.com/forum/uploads/573/pcenginepad.jpg

Another mild case
https://res.cloudinary.com/lmn/image/upload/fl_lossy,q_80/f_auto/v1/gameskinny/6a43e03c0194a54b7cb926dab694f3d5.jpg

Whatever is causing that - it doesn't wash off with any of the conventional means I've tried - but CAN be chiseled out/off with a dental pick. Both of my JP pads have this, one is worse than the other, my US pad does not. I'm at a loss.

[Necromancer]

Maybe damage caused by harsh cleaning chemicals?

[turboswimbz]

I'm not at home at the moment, but the picture in this ebay listing shows what I am talking about - check out the D-Pad on the bottom-left controller compared to the others

https://www.ebay.com/itm/NEC-PC-Engine-Controller-Set-Core-Grafx-II-4pc-Japan-Import/232458653040?hash=item361f9d8d70:g:tFMAAOSwXwBZm-JD

Here is one where its just starting
http://www.ukvac.com/forum/uploads/573/pcenginepad.jpg

Another mild case
https://res.cloudinary.com/lmn/image/upload/fl_lossy,q_80/f_auto/v1/gameskinny/6a43e03c0194a54b7cb926dab694f3d5.jpg

Whatever is causing that - it doesn't wash off with any of the conventional means I've tried - but CAN be chiseled out/off with a dental pick. Both of my JP pads have this, one is worse than the other, my US pad does not. I'm at a loss.

That appears to be damage (pitting in some cases?) to the plastic structure itself as such no amount of washing is going to to solve it. Nor will H2o2 as this isn't the same as yellowing.  I've seen with these ABS plastics a tendency for the plasticizers to leach out and form solids on the surface of a plastic. (sometimes through oxidation, which would give blacks plastic a white haze, maybe similar to this?).  I'm guessing these were most likely caused by aggressive cleaning with a chlorinated/Alcohol solvent, or through excessive heat (possibly over time).  A totally different process than yellowing.  What should work fairly easily and time efficiently is actually sanding down the plastic to uncover a new layer/get rid of the layer on top of the original plastic. my suggestion would be to try a pumice cleaner with a tooth brush or even better a Mr. Clean magic eraser, anything that will lightly sand.  this will remove it without you having to pick off little by little.  Hope this helps as I am just guessing, I did quite a bit of lab work with ABS plastics back in graduate school, and this is my best guess based off that for a somewhat easy solution.  perhaps somebody here has actually experience with it and can help better than I.   

[tjsnh]

That's incredibly helpful, and insightful. I hadn't thought about sanding/grinding/etc down the outer layer. Given the issues with the CD-ROM2 gear ... aging poorly ... I suspected that the D-Pads (or some batches of them) may have been manufactured from a plastic with different aging process or something. Heavily annoying problem - I take pretty good care of my stuff, and almost all of my retro hardware is mint/near-mint EXCEPT these couple of d-pads ..

Ah, the joys of retro gaming ...

[turboswimbz]

good luck.  In case your interested or anyone else.  Here is a wonderful and easy to follow scientific paper explaining different types of polymers and how you might stop them. (specifically plastics and Styrofoam) decay. 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4320144/

Also you may want to try this:

https://www.amazon.com/303-Aerospace-Protectant-Anti-Fade-Spray/dp/B00CP65BBU?tag=vs-auto-insert-amazon-20

It's a UV restorer protector, it just may work also.  I've talked to a bunch of car guys and they perfer this to armorall and mothers products.

[Vimtoman]

I agree with Necromancer.
It's probably someone de yellowing using a peroxide/washing powder mixture and leaving it on for too long.