removing solder flux

Thread Starter


Joined Mar 23, 2016
I've been making some home projects and have become concerned about removing solder flux from my breadboards. I'm considering scrubbing the flux off with isopropyl alcohol. I do wonder though would it damage the components already soldered. i.e. resistors, capacitors. In particular the electrolytic caps. When I worked in electronics over 20 years ago I didn't pick up on the deflecting processes. Can anyone weigh in?



Joined Jan 18, 2008
The only devices I would be the least bit worried about with 90% isopropyl alcohol (IPA)would be optical devices and unsealed relays and pots. On relays and pots, you may get gunk on the contacts -- depending on how clean your IPA is and technique. As for optics, it is relatively safe, but if there is a lens, you may get a smudge. You also run the risk of removing any lubricant on shafts. Are you using 90% or 70% isopropyl alcohol ? 70% IPA is less aggressive but may not be as effective at removing the flux as 90% IPA is.



Joined Oct 29, 2013
Denatured alcohol works well for general flux removal, and cleans the workbench well also. In addition to the warnings above, it's flammable so be careful to make sure it's all dried up before turning anything on.


Joined Jan 18, 2008
Denatured alcohol is a mixture of ethanol plus any one of several "approved" denaturant mixtures. I believe what brew is used varies by country and end purpose. Some of those mixtures contain chemicals that are more aggressive toward plastics. If it works for you, then no problem. My personal favorite is absolute alcohol + a little acetone (very roughly 3:1). Of course, acetone is aggressive toward some plastics, and I do not use that mixture when soft (e.g., styrene like) plastics are present. It works fine with nylon and the like. ABS and PVC car affected, but only very slowly. It is very quick acting and evaporates quickly without leaving little water droplets or haze behind. That is its main advantage over 90% IPA.



Joined Mar 30, 2015
I use 99% IPA with a short bristle horse hair brush for most of the cleaning and finish with a commercial flux remover. Drug stores typically carry 90-91% IPA, I bought the 99% from a pharmacy associated with a hospital. Higher water content will leave more residue.


Joined Apr 28, 2012
lighter fluid.

Liquid butane if you are desperate (dont say I didnt mention explosion risks).
A small PCB just straight from the bottle is OK.