Cleaners for plastic? - Page 1
Forum section: electronics / repair

author: MikeK
author_rank: Super Contributor
timestamp: July 05, 2022, 11:06:02 pm
content: Before my part arrives for fixing my Keithley 175A (https://www.eevblog.com/forum/repair/keithley-175a-not-working/) I might as well clean up the case and display. I have these cleaners in my house:1. Simple Green2. Isopropyl alcohol3. Windex (with Ammonia-D)4. Formula 4095. Sprayway Glass Cleaner (Ammonia Free)Will any of these definitely ruin the plastic? I'm especially worried about the LCD.

author: David Hess
author_rank: Super Contributor
timestamp: July 06, 2022, 12:45:18 am
content: Alcohol will fog some plastics. I like to use naphtha, which is plastic safe, and then water with a little bit of dish soap, but often I use Windex because it is more easily available.

author: MikeK
author_rank: Super Contributor
timestamp: July 06, 2022, 12:59:09 am
content: Thanks. I thought there was something about ammonia being bad? The glass cleaner (Sprayway) that I use for my car brags about being ammonia-free, which I thought was to prevent damaging rubber and plastic. I had no idea naphtha was plastic safe. Good to know.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 06, 2022, 09:45:33 am
content: All of the solvents the TStarter name are OK on most plastics. The polystyrene is quite sensitive. Jewel cases used for CD's are an example. I have never tried isopropyl alcohol, but even light naphtha (e.g., VM&P Naphtha) will cause slight fogging.If you are just removing accumulated dust, finger prints, etc. I would recommend any of the water-based cleansers. If you need to remove goo, I typically use naphtha but be careful on any clear plastic. It can cause crazing, which doesn't necessarily appear immediately. Butter is another very mild solvent for goo. The mildest "solvent," of course is not to use any solvent at all. Use a piece of tape (e.g., masking tape) sticky side out. Press and quickly pull off. You might need to repeat.

author: David Hess
author_rank: Super Contributor
timestamp: July 06, 2022, 02:08:33 pm
content: Quote from: MikeK on July 06, 2022, 12:59:09 amI have never had a problem with ammonia cleaners like Windex that I remember.Quote from: jpanhalt on July 06, 2022, 09:45:33 amI have had problems with VM&P naphtha being contaminated with other things, while purer naphtha was not a problem.QuoteHeating with a heat gun helps soften any adhesive.I have read that glacial acetic acid is good for removing labels, but it never worked well enough to justify dealing with it.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 06, 2022, 05:29:33 pm
content: Re: naphthaOf course there are various purities. I tend to use the KleanStrip version and avoid Sunnyside solvents whenever possible. Similar cleaners are sold in automotive finish stores under various names. Some contain a small amount of toluene or xylenes. Those might be a problem on polystyrene.

author: MikeK
author_rank: Super Contributor
timestamp: July 06, 2022, 06:30:58 pm
content: Windex and Simple Green worked just fine. Tried everything on my other meter, but can't get this fossilized label off.

author: jpanhalt
author_rank: Super Contributor
timestamp: July 06, 2022, 07:05:27 pm
content: Gentle heat can help. After that, you run the risk to damaging the plastic with stronger cleaners. Just leave the label.

author: MarkF
author_rank: Super Contributor
timestamp: July 06, 2022, 07:10:33 pm
content: I use WD40 to remove store pricing labels.You might need to let it soak for a while.Then clean with one of the cleaners discussed here.

author: DaJMasta
author_rank: Super Contributor
timestamp: July 07, 2022, 05:02:48 am
content: For label adhesive residue, something with lemonene is usually my preference - something like Goo Gone. You just wipe it on (it takes a couple passes to clean, so I usually apply to a paper towel and then use that), let it soak, and the label gunk should be softer and less sticky, and usually comes off with a little manual scrubbing or peeling.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: July 07, 2022, 12:45:19 pm
content: Oily cleaners like Googone can help a lot. Some folks use Mineral oil, Vegetable oil, peanut butter, butter. The idea is to let it soak in the oily solvent, Put a small piece of paper towel on the spot and saturate it with the oily solvent.

author: HighVoltage
author_rank: Super Contributor
timestamp: July 07, 2022, 01:05:55 pm
content: I have several of the old brown Keithley instruments.They clean up very nicely with some alcohol.And when I am done cleaning, I wipe the plastic with some very thin oil (Liquid Paraffin or White Oil), let it sit for a few hours and then wipe it off with a clean cotton cloth.After this procedure, the housing will look like new and will stay like this for years to come. Somehow this brown plastic material absorbs the thin oil well.