How to make your dull knobs look shiny new

From the Make Flickr pool, linux-works shares his secret for making dull instrumentation knobs shiny.

201204141708I bought a very old (1960's or 70's, roughly) power supply from eBay, in need of rejuvination.

Look at the two red knobs, top group and bottom group. both knobs were removed from the device, very thoroughly cleaned with hot water, soap and a sponge, then air dried. I was hoping that simply cleaning the knobs would be enough. it wasn't.

So, how did I get the top knob pair to be so nice and shiny?

Triple antibiotic ointment!

The stuff that comes out of a small tube that you use on skin cuts before you put a bandage on ;) it has a vaseline like base and this appears to bond (?) to the plastic or somehow refresh it.
How to restore shine to faded knobs


  1. I’m no chemist, but I’d be cautious there.  If it is petroleum jelly, or some other petro base, it may eat and weaken plastics as it does for rubber.  I’d say stick with Armor All, designed for the job.

    1. 100% with George on this. Keep petroleum based ANYTHING away from old plastic-like materials. 

  2. When it finally happens and Atwood’s second flood comes, I want to be stranded in a remote location with just enough food and water to survive… oh, and these sorts of people. We’ll have a well up and running in no time, and it’ll be shiny!

  3. I had a dull knob, once.  It was so worn from overuse that no one wanted to handle it.  The secret to its resurrection was a strict regimen of forceful polishing.  No matter how laborious the task, no matter how tired I became, I kept at it.  In time, my knob glistened like sunrise on a dewy meadow.  

    I’ve seen women with nice buttons, but my knob beats them all.

  4. Not what I expected to learn about when I followed this link…and yet the advice is still sound.

  5. ” very old (1960’s or 70’s, roughly) ”

    hey man, i was born in ’64 – i’m not VERY old. maybe ‘kinda’ old, or ‘sorta’ old, but not VERY old. that’s just harsh.

  6. sadly, as an “old guy”  also 1964,   and a restorer of vintage motorcycles,   petro jelly will make them look awesome.  for about a month,  if you never ever touch them or allow any dust on them.   Spraying Lemon Pledge will do the same thing.  short term.

    Meguire’s automotive grade plastic polish works wonders.    you have to clean, then seal with something,  a polish or wax is better than a petro jelly or oil.

    But?  for right now?  those are some mighty well polished knobs you have there sir!  :)

    1. It certainly destroys patent leather shoes. They look all gleaming for a while and then the cracking starts.

  7. I’ve done wonders with Q-tips dipped in rubbing alcohol.  Works great on plastic food container lids (remember to wash thoroughly before using!), action figures and glass cookware too.

    1.  I used to swear by alcohol for cleaning plastic. Then I tried to clean a piece of PMMA, and it just about shattered, but in slow motion. The effect was fascinating and horrifying at the same time (it was an important piece). Unless you’re sure which plastic you have, alcohol bad, stick to soap and water.

      1.  Ditto: you have to be very, very careful when using any solvent (actually, make that any chemical) with plastics.

        For example, never, never, never use regular glass cleaner with plastic eyeglasses; the ammonia crazes (microfractures) the plastic and makes them cloudy.

  8.  I’d say you have too much time on your hands, but since I’m reading and commenting on what is essentially a long-form “Hints From Heloise” column, I’ll pass.

    1. Hey now, Dave. I learned a lot of good life-tidbits from Heloise back in the day.  (I can get virtually any stain out of any fabric, at any time!)

      Now, I am learning a lot of even better life-tidbits from BoingBoing. (I can polish knobs like the dickens!).

  9. Doesn’t triple antibiotic ointment contain antibiotics? Are you trying to toughen up the local bacteria?

  10. wrong oil/grease on plastic = plastic turning into jelly.  Sometimes it takes hours, sometimes days.  Yamaha had a problem with it on a number of their keyboards and had to replace a ton of ’em when the keys started deforming and sticking.  I’d be careful before trying this on anything you care about.

    1.  Yeah. In the lab, we had a peristaltic pump whose rollers were annoyingly squeaky, so I hit them with some WD-40 before fitting the rubber tubing into the pump and turning it on. About 20 minutes later, I noticed a leak, and then noticed that the tubing was totally disintegrated and shredded … that was fun to clean up.

      Felt like an idiot, too. Everyone knows not to use Vaseline with condoms for exactly that reason. I really should have guessed about WD-40 and rubber tubing. (Okay, okay, insert dirty joke here. But seriously.)

  11. I’ve been using petroleum-based products on my knobs for years without any adverse effects. They stay shiny, like they were new.

  12. I’m with the people saying this is a bad idea. I think it’s a bad idea.

    It might make the knob look shiney and new right now, but for all we know it might have started a reaction which will cause the knob to decompose within years.

    I hope Boing Boing will come back in 20 years and look at the condition of that knob again.

  13. Vaseline and its cousins eventually evaporate leaving you with the same dull finish after a few weeks.  Waxes on the other hand stay around for a year or so if you don’t rub it off.  If you want a finish that lasts longer, you’ve got to go polymeric, like Meguilar’s NXT.

  14. Are the results as impressive when you work on someone else’s hardware? My husband’s knobs need refurbishing and this has whet my appetite to tackle that spring cleaning chore.  

    1. The original ointment contains three different antibiotics: bacitracin, neomycin, and polymyxin B, in a relatively low molecular weight patented base of cocoa butter, cottonseed oil, sodium pyruvate, tocopheryl acetate, and petroleum jelly.

  15. Unless your wound is a bite, the use of local antibiotics is pointless and only serves to induce bacterial resistance to antibiotics. Use warm water and soap, that´s all that is needed.

    1. But go see a doctor if it still hurts like hell after a day or if you see any pus. Sepsis ain’t fun; believe it or not, any wound can potentially introduce dangerous bacteria that cause sepsis.

      There are better ways to die.

      (Also: don’t take any medical advice from BB comments. Seriously.)

  16. Well – der, anything greasy will make it look better. A bit of solbolene cream, some olive oil, any ointment in the cupboard. Armor All also. Though Armor All can make your hand slip when twirling the knob, depending on the gear this may be dangerous. I have experience with once using it on a motorcycle seat and regretting it for quite some time.

  17. Alcohol can dissolve some plastics but not all, though the knobs are most likely polystyrene.  But the best solution is to use a fine auto polish to remove the top layer of oxidized material.  Ever notice how old red cars can look dull too? The polish removes this stuff on top.  Vaseline is a grease and will not evaporate, but simply is a temporary and slippery fix.  Go with the car polish, not the Pledge.

  18. Syliva would definitely make a knob shine and if applied correctly also harden it. Sometimes to the point of exploding! 

  19. I have also bought on Ebay and restored a few pieces of old test equipment from the same manufacturer. (The trademarked turquoise color gives it away, but I don’t want people bidding the stuff up too much. It’s like getting antique Patek Philippes for 1/20th what they cost new.)

    I recommend Armor-All for the knobs, a Dremel with a felt tip and jeweler’s rouge for the aluminum edging, and Radio Shack  “Precision Electronics Cleaner”  to clean out the insides (other contact cleaners also work fine). Replacement knobs are also often available on Ebay.

    Edit: Well, I won’t be that much of a dick today. Tektronix is the very prototype of “wonderful things” . Take a look at the gold-plated, sinuous insides of this model 453 Tek oscilloscope. I have one almost like it (453A) which spent over 30 years in a sooty power plant. The aroma of machine oil and ozone soaked into it permanently, it’s like the essence of electricity.

    1. Now, that’s what electronics are *supposed* to look like.  And might I just say that is an impressively long shaft in the first PCB photo :) ?

  20. These things are plastic.  There are many types of plastic.  Each plastic, if you research it a tad, usually has a long list of items to which it has been exposed with the resulting effects listed.  Unless you know the type of plastic, and the composition of the chemicals to which YOU are exposing it, it is a complete crap shoot and (no offense meant OP), stellar bad advice to advocate a particular treatment.  Also, since the knobs (if old) have been PRE-EXPOSED to a complex, unknown environment for a long time, the composition of the surface isn’t even known for sure.  The best way (IMO) to get shiny knobs is to replace dull ones with new shiny ones.  Even then, it’s temporary, by definition.  They are consumables.    However, if they activate their related functions reliably, the cosmetic aspects are ‘preferential’; i.e., unimportant to their primary purpose.    (The MSDS does not normally have compatibility lists, but the spec sheet for the plastic used DOES, if you can find it.)

    1. I presume you’re talking about chemical resistance charts (ie: Cole Palmer), though identifying the plastic type is not always simple. There are some basic flame tests you can do, but some require instrumentation.

      If you have located replacements anyway, you’ve got nothing to lose by cleaning.

      Geez, I can’t believe 48 posts on friggin’ knobs and I’ve left two. At least most of them are humorous.

      And I’ve left two serious ones. Guess I need a life.

  21. To summarize:

    – Triple antibiotic ointment can make old plastic knobs look new, at least in the short term.

    – It’s presumed that the petroleum jelly is causing the desired effect, and that the added antibiotics are merely hastening the spread of antibiotic-resistant pathogens.

    – Many substances can make old plastics look nice for a short while, but worse in the long run, and it’s hard to tell which are helpful for which items.

    – The  medical implications of antibiotics’ loss of efficacy are a lot less important to the people who post on BoingBoing than the fact that “knob” is a slang term for “penis”.

    All in all, this piece is a lot less than meets the eye; it’s a shame it was posted, and a disgrace that no moderators have highlighted what a blatant abuse of a precious shared resource it is, even after it was pointed out in the comments. I’m sure somebody will call me a knob for saying so, but it has greatly diminished my view of BoingBoing and of Mark Frauenfelder.

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