I have a few IBM ThinkPads from the 1990s, and they had a rubberized sort of finish to them that feels sticky to the touch now. How should I realistically go about cleaning them such that they won't be destroyed or look uneven in their finish?
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4The only (somewhat) acceptable way is to remove it at whole :(– RaffzahnMar 11, 2022 at 3:52
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How would you do that without damaging and leaving uneven then?– Brian ReadingMar 11, 2022 at 4:17
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2In my view, this is more than cleaning. The plastic may actually be clean, just changing chemically. Or, do you mean it's dirty too? Not sure it matters because the end game is to replace the item, or treat it somehow to limit the damage and or bring it to a useful state.– SpudMar 11, 2022 at 4:20
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2I mean chemically-changing stuff that breaks down and becomes sticky. This usually can't just be wiped-off.– Brian ReadingMar 11, 2022 at 4:45
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2@bmreading It will always end up destroying part of the surface. It's the curse of that surface composition. Any solvent removing the 'muddy' layer will as well attach the underlaying body.– RaffzahnMar 11, 2022 at 9:50
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5 Answers
Short version: use 70% IPA (isopropyl alcohol, A.K.A. rubbing alcohol) and cotton pads. Higher concentration IPA should be fine too, but isn't necessary. Gently rub the sticky mess with a cotton pad soaked in IPA solution, let the surface dry fully between passes, repeat until sufficiently clean.
TL;DR: The body of the ThinkPads produced in early to mid-90s is usually based on what appears to be ABS plastic, late 90s to early 2000s - a mix of ABS plastic and metal alloys, typically magnesium-aluminium (e.g., T20-T23 and A20-A22 series have magnesium-aluminium lid and plastic lower bodies, 770 series have metal lower bodies - not sure about their lid), later 2000s until around 2015 - again ABS plastic on the outside (often reinforced with carbon fiber or fiberglass in the lid) with magnesium-aluminium alloys used for internal frame. Up until recently ThinkPads had a separate coating made out of a polyurethane-based rubber-like polymer that aims to be self-healing - prior to late 90s it was used to cover the whole laptop, since late 90s (when IBM switched to using letters for designating families instead of numbers - e.g., A-series instead of 7XX, T-series instead of 600, etc.) they used that coating only on the lids, and AFAIK around 2015 Lenovo started phasing out the use of that coating altogether, though it's been a while since I pulled out my P50 and P51.
The problem with that polyurethane coating is that under certain conditions it degrades. I'm not sure what those conditions are exactly - some people suggest it may have to do with oils, high humidity and temperature, or exposure to sunlight. When it degrades it becomes more pliable and tacky than intended - those are the very same properties that allow the coating to be self-healing when they're present in moderation. Unfortunately, this degradation is a change in chemical structure of the material - AFAIK, it comes from polymer chains getting shorter. As far as I know there isn't anything that can be done in-situ to restore the material's original properties, so if the coating on your ThinkPad became tacky your only recourse, I'm afraid, is to clean it off.
I got a 701C with the original IBM bag made of bonded leather, and that bag just leaves black sticky residue on everything it touches, the fake bonded leather pretty much just falling apart into chunks of leather fibers soaked with polyurethane. The coating on that 701C was in the same condition - you take the laptop in your hands and you get black sticky mess all over your fingers. I'm afraid if your coating reached that point there isn't anything you can do about it except to strip the sticky layers. In case of my 701C I used isopropyl alcohol with cotton pads to clean it. I ended up eventually stripping it completely because after removing just the sticky layers it looked very patchy and ugly, but YMMV.
You shouldn't need to use anything more harsh than IPA, and 70% solution is good enough to get the job done. Please don't use anything containing acetone, MEK, or similar solvents, as those will outright dissolve the plastic underneath. Keep in mind that high concentration alcohols can cause some discoloration and minor damage to ABS plastic as well, especially at high temperatures and long exposure times, so don't soak the parts in alcohol and don't heat either the parts or the cleaning solution. But in my experience there were no major side effects of using 70% IPA to clean my 701C and let it fully dry between individual passes.
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1Can confirm from personal experience with ThinkPads and certain mice that isopropanol and a lot of patience are exactly what you need. The exact percentage of isopropanol is not particularly important. I tend to have 90% IPA sitting around for use with computers/electronics, so that's what I use. But I've used 70% IPA, too (which is preferred for medical/first-aid usage, as it has better bactericidal properties). I've never seen 90% IPA discolor or damage plastic, but I've never immersion-soaked any plastic in it, either. Just wipe/rub on and let dry. Mar 12, 2022 at 5:06
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1@CodyGray Yeah, I never soaked any plastics in IPA or ever experienced any issues using IPA on ABS plastics either. But ABS plastic is known to be affected by alcohols, so I thought it would be a good idea to mention that just in case. Mar 12, 2022 at 6:30
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1> "polyurethane degrades" The same thing happened to the rainfly on my camping tent. Nothing lasts when it comes to plastics.– alexwMar 13, 2022 at 1:22
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4@alexw that depends on a type of plastic. Some can last for many decades, e.g. Bakelite. And in the context of something like laptops - metals don't last either. If anything, the all-aluminium modern machines like MacBooks or HP Elitebook very easily accumulate permanent damage that's nigh impossible to repair without replacing the whole machine. I dropped my all-metal 15" late 2015 MBP onto a carpet from my lap and the hinges got bent. I dropped my plastic ThinkPad from shoulder height onto concrete and other than a crack in a replaceable plastic part it still works like nothing happened. Mar 13, 2022 at 6:57
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2@moonwalker I cleaned my Gemini PDA keyboard with IPA and a bit of it got inside. Within one week, keycaps started to fall out. I am not sure this was the reason, but I saw no other reports of this keycaps issue... Mar 14, 2022 at 6:32
Your choice is one of sticky or ugly.
There is no nice solution. The only way to make it less sticky is to remove it, which will always also attack the body below. The body is (usually) based on the same type of plastics, thus solvable (aka attacked) by the very same solvent usable to remove the surface coat.
To do so various solution can be used. From ethanol to isopropyl alcohol all the way to paint thinner.
The core problem in doing so is that application must be as even as possible, and related to the amount of material to be taken off. This can be done in essentially two ways.
'Rubbing' with a Solution and Linen
Here the solution used is applied only in small amounts and rubbed off right away. It works a bit like sanding, like taking off skin with a sand-soap-mixture. The downside is that it will almost always result in an uneven surface, although this can be aesthetic as well :)) Resulting surface depends a lot on timing.
Pasteify the Solvent
Another way to apply it in a (more) even fashion is by turning it into a paste. This can be done by using a water-soluble solvent such as isopropyl alcohol and mix it with water and corn starch. This can be applied, dried and, depending on mixture, rubbed away or pulled off. The resulting surface depends much on prior condition (which usually is already uneven) and mixture. So not really something to be done without prior experiments to find the right one.
Bottom line: Keeping the original texture and operating it is next to impossible.
answered Mar 11, 2022 at 10:12
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6The body is not usually based on the same type of plastics. The coating on ThinkPads is polyurethane-based rubber-like substance that aims to be self-healing, but underneath it there is a hard shell. On earlier ThinkPads AFAIK it is a plain ABS plastic, later models may use fiberglass or carbon fiber reinforced plastic or a magnesium-based alloy. Unless you use something more aggressive than alcohol they'll never dissolve. E.g., my plastic 701C resists ISA pretty damn well. Models like T20-T23 and A20-A22 use magnesium alloy in the lid, good luck dissolving that with even paint thinner. Mar 11, 2022 at 14:34
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1You're more likely to damage the plastic underneath if you rub too hard. Be gentle, and the surface underneath the coating should remain intact. Mar 11, 2022 at 14:38
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2@moonwalker: In that case IPA is ok, but readers should be aware that acetone and many cleaning solvents (likely including stuff like Simple Green, Krud Kutter, Goo Gone, etc.) will attack ABS. Mar 11, 2022 at 15:22
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5@r-github-stop-helping-ice Oh hell yes, absolutely, for the love of whatever you believe in, you should never let anything like acetone and other harsh solvents to be anywhere near any plastics. Alcohol - perfectly fine. Acetone - hell no. Even mere 70% IPA should be good enough to clean out the sticky gunk, there is simply no good reason to use anything more harsh. Except maybe 90-98% IPA, that's still perfectly fine. Mar 11, 2022 at 21:08
Bit of frame challenge here, but if your goal is just that they are 1) not sticky, 2) not damaged, 3) not uneven in finish...
Add a vinyl wrap over top of the sticky plastic. If you can't find a pre-cut one for your exact model, just get a sheet of adhesive-backed vinyl and a hobby knife and cut to size.
As a bonus, you also get a wide array of colors, prints, and finishes to choose from--either to recreate the look of the original or to go with something completely different.
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I'd remove the degrading plastic first, so that you're not just covering the problem up while it continues to worse underneath... Mar 14, 2022 at 11:18
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@nick012000 It's only a cosmetic problem (degrading rubber coating that's only on the surface) so covering it up actually solves the problem, the worst that can happen with covering it is that eventually it loses adhesion and your wrap peels off which can be solved by another wrap. Being too aggressive about removing the coating might turn it into a real problem, though. Mar 14, 2022 at 14:58
I had that on a Logitech keyboard, at the wrist rest. I ended up just flinging the removed rest into the washing machine. Came up a treat! Perhaps I just got lucky since it had been sticky for 5 or so years (I used it little). I would not recommend stuffing the laptop in there and seeing what happens...
Lighter fluids like Zippo (basically naphtha) gets rid of sticky residue and grease much better than IPA 90% of the time, just dab a little on a rag and rub the goo off leaving a smooth plastic surface.
Depending on the type of coating though, sometimes even naphtha alone might not be able to do the job, might have to break out the scouring sponge for those cases
