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How to remove yellowing from an old Atari case

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#851 tjlazer OFFLINE  



  • 1,745 posts
  • Retro Atari Addict
  • Location:Historic South Tacoma, WA USA

Posted Thu Jul 10, 2014 11:26 AM

Be caureful with that "creme" developer on ST/XE cases, it tends to bloom them.  I would mix some regualr perozide in with that creme developer (60/40) to water it down, that tends to help a lot.

#852 DocRotCod OFFLINE  


    Chopper Commander

  • 108 posts

Posted Sat Jul 19, 2014 12:54 AM

I don't remember what I used as I did it last year, but I did my 1200XL case and brushed it on.  I did get it much brighter, but my case has definite streaks in it.  What is the recommended way to fix this?



#853 biroballpoint OFFLINE  


    Combat Commando

  • 4 posts

Posted Fri Sep 12, 2014 1:25 PM

Hi, I've done a bit of experimenting with 35% Hydrogen Peroxide and UK September sun (cloudy with a chance of no sun) and the results are impressive, but what I wanted to share is the way you can get the stuff to stay on the cases. I dissolved a few spoonfuls of wallpaper adhesive granules into 300ml of HP solution and a small pinch of Oxy stain remover, mixing well. 


http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=140573612932   <----Doesn't work


Wrapping everything in bubblewrap (I ran out of clingfilm)  I placed everything on top of my shed roof at 5am before I went to work. After coming home at 530pm, I unwrapped and washed the cases (1050 & 800XL).


Great results for such a cloudy day but my 800XL top case came out in a bubble wrap rash! So the bubblewrap was a failure. The cases came out a lot better than I expected for just one dull day, and now look brand new (except for the bubblewrap pattern on top of the XL). 


The wallpaper paste was a success though and I now plan to bleach my 65XE & 130XE, along with my 800, which is very yellowed. 


I hope this gives some encouragement to other users to try it. It took me 2 hours to dismantle, clean and treat a 1050 & 800XL case and 1 dull day to expose them to (weak) sunshine. But it worked.



This chemical is <3PH, meaning it is extremely corrosive (acidic) - I got my hands burned not wearing protection, thinking I could avoid splashes etc. It doesn't work to hope you don't get any on your hands (it's painful and turns your fingers a chalky white). 

Thank god I didn't splash any in my eyes! Please be careful and wear some latex gloves and change them frequently as drops can get into them without you knowing. 

And don't touch your eyes either, could be catastrophic :-/


Good luck and give it a go




<<<<<<<<Edited to remove the bad link and replace with valid one<<<<<<





THIS should work (for UK eBay) 


Edited by biroballpoint, Fri Sep 12, 2014 1:30 PM.

#854 Osgeld OFFLINE  


    River Patroller

  • 3,317 posts
  • Location:Nashville, TN

Posted Tue Sep 23, 2014 10:58 AM

I just buy a pile of cheap weak peroxide, pour it in a clear container, add oxy till it stops dissolving and let her ride, maybe a little water to top it off


takes longer, requires good sun but dont do it on a hot day, but I have never had streaking and 10 bucks will make 3-4 gallons of the crap


I am going to try and do a machine this weekend depending on sun, if I do I will post my madness and results

Edited by Osgeld, Tue Sep 23, 2014 10:59 AM.

#855 flashjazzcat OFFLINE  



  • 12,109 posts
  • Location:United Kingdom

Posted Fri Dec 4, 2015 4:47 AM

Oxy exacerbates blooming: be careful with it. I don't bother adding Oxy at all.

#856 Spanner OFFLINE  


    Chopper Commander

  • 110 posts
  • Location:UK

Posted Thu Oct 20, 2016 5:32 AM

You can use electrical tape,thats what I did to my Atari 130XE and it looks alright,I can't stand the case,it looks cheap,you can get in it all different colours.Black I used,you can get white,blue,and orange.but I would use that colour.. ;) I did it to my c64 too.


One question I wanted to ask..If you smoke cigarettes (rollups) can that turn the cases yellow..? 


See how yellow the disk drive is for the C64,will have to do that next in black tape.

Attached Thumbnails

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  • C64 Black.JPG

Edited by Spanner, Thu Oct 20, 2016 5:43 AM.

#857 Paul Westphal OFFLINE  

Paul Westphal


  • 1,126 posts
  • Location:Portland, Oregon

Posted Wed Jan 4, 2017 4:57 PM

This Works, and works better in direct Sun on a hot summer day.

Does not damage plastic.

Some yellow may bleed back, that's why - the longer the better - the first time.

I have used it on 400's, 800's XL, XE, Amiga 2000.Oxyclean-pic.jpg

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