Tuesday, August 25, 2015

Updated Whitening Formula

I have used this on knitting machines, garter carriages, needle pushers, transfer and latch tools and they all come out like they were when they were  made.  All you need is a few basic ingredients and sunshine.  Just remember to remove the plastic items from the machine and or whatever it is attached too as this is meant only for plastic that has been discolored/yellowed from exposure to UV light.  This will not harm stainless steel but will oxidize reactive metals i.e. aluminum, tin, lead and etc.

If you need more information, advice and or encouragement please don't hesitate to email me.  I really like helping people rejuvenate their precious knitting machines to a brand new condition.


1 - Cup 40 Volume Clear Hair Peroxide (purchase at a beauty supply )

1 - Tablespoon Xanthan Gum powder (Wal-Mart Super Center has it in the baking aisle) - used by folks who avoid gluten, a thickening agent that does not need heat

½ - Teaspoon Glycerin (again Wal-Mart or pharmacy in the vitamin area) - this is optional - it is used to help the solution "stick" to the plastic

½-1 - Teaspoon powdered hair lightner - I have used Basic White (Clairol) and Blondor (Wella) - both available in a beauty supply - they are sold in single use packets which will last a long time as so little is used, any brand will work

In a blender, pour in all of the above, blend for approximately 5- 10 seconds.  The mixture is done.  It wont harm the metal blade in the blender as they are stainless steel.

I applied to the surfaces of the plastic using latex gloves (hair peroxide is a much stronger version of the one we use on minor cuts) and a silicone pastry brush. Once all areas were well covered, I either placed them in a zip-lock bag or wrapped them in kitchen plastic wrap (to repent drying). Now for the important step...place in the sun! The UV rays that caused the yellowing will now act as the catalyst to remove the yellowing. After an hour in the sun, the difference was incredible. I check for "dry" spots and reapplied if needed. The "whitening" process took 2- 4 hours depending on how yellow the piece was. The items can also be placed under a UV light indoors, not a black light.  When all of the yellow is gone wash the plastic in a mild dish detergent, rinse and dry well.

Note:  For areas on carriage covers and etc. that are "set-in" to the beige/white plastic, (usually these are tan, grey or other color) I cover those with blue painters tape then apply the whitener.


  1. will it not make the plastic brittle? Have you noticed any re-yellowing after some time?

    1. Hi Johan, no the plastic is not effected at all and does snot get brittle. If the plastic you are returning to it's original color is eposed to the same elements (sunlight/UV light) it will yellow over time just as it did before. The first machine I did this on is still pristine in color with no yellowing and that was years ago. I also do not have my machines in the studio exposed to sunlight or refelctive sun rays. Hope this helps.

  2. Hi Tom
    I wondered if you would buy the ingridiens for me and post it to me in Denmark.
    There are many of the things I think I cannot get here in DK. I will off course pay you up front.

  3. Tom, I have the same problem as Hanne. Here in Sweden most of the ingredients is difficult to find. Maybe there is one or more websites to order from? If so, please post links :-)

  4. The biggest problem I will have is finding sunshine for that long in one day Looks like next week will be all rain (sigh) Guess I'll spend the week gathering supplies

  5. What a marvelous tip. I will definately be using this. Thank you for being so clever.

  6. What you are using is a powered bleach. I don't think you will actually need to put it in the sunlight, but don't leave it on for any longer than 40 minutes. It ruins hair - I hate to think what it would do to plastic.

  7. E-bay is a great place to get ingredients to make this mix for anyone having difficulties. I am only using a large bottle of Hairdressers cream peroxide with great results...nothing else in the mix! It spreads on great and stays in place.

  8. @Mandy This process is a chemical reaction rather than just a bleach, and thus the UV rays are an important part of the process. It is so that the Bromine that leeches out of the plastic and settles on the outer layers, yellowing the plastic is catalysed to the H202. I did this with a Singer 323's carriage that was so damaged by sun exposure that the whole machine was yellowed to brown! You could even see a brown liquid come off the plastic after the process was done. I found the 40Vol (12% H2O2) at my local pharmacy. I also used a UV lamp at night (as it has been winter here in New Zealand) in conjunction with the sunlight to speed the process up a bit.