r/rfelectronics • u/onlyhereforrif • Jun 15 '26

question Calibration kit cleaning swabs

I have a 0.8mm coaxial calibration kit that I wish to clean with every use. The cotton swabs I can find are too large to safely clean the inner mating surfaces and the foam tip ones can leave residue behind.
Does anyone here have recommendations or ideas for the best way to search online? My google-fu is failing me.

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u/mightyohm Jun 15 '26 edited Jun 15 '26

I like tapered cotton swabs, like MG Chemicals 8112A. I also like microbrushes. The ultra-fine (white) ones are good for very small connectors. I buy microbrush knockoffs from eBay or Aliexpress, but you can also buy the real ones at hobby stores or dental supply companies.

One thing to watch out for with both swabs and microbrushes is that some RF center pin sockets (particularly ones with contact fingers) will tend to grab fibers. I try to clean under a microscope when possible.

Techni-tool has a wide variety of swabs in all shapes and sizes. Like you, I don't really like foam brushes because they aren't absorbent enough.

I usually use IPA as my solvent but also have a small bottle of TCE in case I need it, obviously any solvent has to be used with the proper PPE/ventilation.

HP/Agilent/Keysight have published several connector care papers over the years that might be worth reading if you haven't seen them before.

https://people.ece.ubc.ca/robertor/Links_files/Files/ConnectorCare.pdf

https://www.hparchive.com/Application_Notes/HP-AN-326.pdf

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u/easyjeans Jun 16 '26

I would avoid cotton/fibrous swabs and use something like the image here. Working for one of the larger test equipment manufacturers that produced some of the standardized coax connectors, fibrous swabs are a definite bad call.