# What are the best chemical liquids to clean metallic surfaces?

I'm just a simple man curious about things. I've no big understanding of chemistry. I had this question today in mind. What chemicals could I use to achieve the cleanest metallic surface?

For example, I could first start by using isopropyl alcohol to remove all dirt and oils. But there are other liquids such as acetone and acids.

If you were a chemist, how would you clean a metallic surface?

• Well, what firstly comes to mind is that how "strong" the stain I'm dealing with is. – It's Over Mar 11 '15 at 19:27
• Let's say I scrape everything off first. – bodacydo Mar 11 '15 at 20:37
• I'm going to assume clean as to kill pathogens – Asker123 Mar 12 '15 at 0:27
• Sorry no - clean to make it thermally more conductive - clean from dirt, oils, rust, oxidation, etc. – bodacydo Jul 20 '15 at 2:02

Assuming clean means anti-pathogenic, I would use Hydrogen Peroxide "oxyclean" since it can "clean" metals by removing pathogens. $\ce{H2O2}$ is marketed in various strengths. 1% dilution can kill up to 99.99% bacteria in 30 seconds.

Any butyl based cleaning product is a very good degreaser but it may harm rubber products.

Check here and here for more.

• Sorry no - clean to make it thermally more conductive - clean from dirt, oils, rust, oxidation, etc. – bodacydo Jul 20 '15 at 2:03
• Thanks for the great return after like 3 months? – Asker123 Jul 21 '15 at 23:29
• :) :) :) :) :) :) – bodacydo Jul 22 '15 at 3:14

Cleaning metal surfaces in industry is a very common problem. Common enough, in fact, that an industry has grown up around the solution. Halocarbons, either singly or in combination, are excellent at removing contaminants from metal surfaces (see the "uses" section in this link). Typically a perforated wire basket is filled with the parts to be cleaned and then the basket is suspended above a bath of the halocarbon liquid. The liquid is brought to reflux (typically less than 100 °C) and the vapors dissolve all impurities and the part comes out clean. The dirty vapors condense, the impurities eventually precipitate out and clean vapor is ready to repeat the cleaning step. The vapors are contained in the unit so atmospheric contamination is minimized. This approach works well for intricate parts or parts with hard to access cavities.

Simple ultrasonification, using either an organic solvent or water containing a cleaning agent, is another possible cleaning method.

Hmm, if like thinking of a heat-sink mounting surface for a processor IC I think you may be getting a bit over zealous.

The form of heat transfer does matter, if radiated, a dirty black surface is better, if using convection a rough finish might assist and if as you say conducted the intervening gap filler will dictate more than a surface contamination unless the surfaces are flat enough to atomically adhere.

An air gap between two rough clean surfaces will have poor conduction.

Soldering with suitable alloy or placing a conforming powder filled spacer or grease are the usual methods to maximise thermal conduction. For this you would use one or two practical solvents to strip oils, an ionic cleaner to remove salts and mechanical scrubbing to remove oxides and entrained particles.