Sciencemadness Discussion Board

Glassware cleaning procedures

binaryclock - 2-6-2013 at 05:16

What type of procedure does everyone use when cleaning glassware after using mostly water soluble chemicals such as acids, chlorates, etc?

Right now I'm just giving them a good bath in soapy water, agitating the glassware or items to be cleaned, brushing with a brush where possible, then rinsing very well and setting them out to dry.

I have acetone, but only have used it a few times as I haven't really found something I haven't been able to get extremely clean with just soap and water.

Should I be using acetone on all glassware for the final rinses or is the soap/water method okay for non oily, water soluble chemicals?

Hexavalent - 2-6-2013 at 06:11

Personally, I rinse all glassware in cold water, clean thoroughly in hot soapy water, rinse with hot water, and then rinse with de-ionized water.

If anything persists, I use scrub brushes and this usually works. Adding boiling water to the glassware at this point also helps significantly, in my experience.

Failing that, for anything organic that's hard to remove, acetone is my first try. If that doesn't shift it, adding salt to the acetone and shaking vigorously usually works wonders.

For anything inorganic that's hard to remove, 25% hydrochloric acid is my first try. If that doesn't shift it, heating the acid and shaking usually works.

If none of these methods work, I then try soaking in NaOH in ethanol. If that doesn't work, then I usually just forget about it, and only use the glassware in "messy" reactions. If it's an expensive bit of glassware, I'll try aqua regia, and then piranha solution. I've never needed to use the latter, thankfully, it should really only be used in extreme situations, as it is incredibly corrosive, toxic, and can explode on contact with organics.

Endimion17 - 2-6-2013 at 06:55

Why not using the search engine? This has been discussed ad nauseam.

plante1999 - 2-6-2013 at 07:03

The tap water here is pretty pure, so I usually wash with tap water and my hands (gloves). If it doesn't come up, I use 96% sulphuric aicd and potassium dichromate at approx 60-100 C, then wash it. I never saw something resist to such treatment.

If I know I will use the glassware for something sensitive, I will do a final wash with 99.9% methanol (available at my hardware store).

binaryclock - 2-6-2013 at 09:46

Thanks guys, that's very helpful and I'll keep your methods in mind.

I did use the search engine actually, and tried a few different searches, going to page 3 both times. Maybe I was searching the wrong keywords but I was persistent because I didn't want someone to be "that guy" and say use the search engine.

As far as using Google, I did not use that as I trust the knowledge of the members on this forum and wanted to hear straight from them.

[Edited on 2-6-2013 by binaryclock]

Hexavalent - 2-6-2013 at 12:13

Personally, I find resorting to using sulfuric acid/dichromate (essentially chromic acid) immediately after tap water a little extreme, especially considering the expense and difficulty of obtaining dichromate for many people, in addition to it's high toxicity and potential carcinogenicity.

bfesser - 2-6-2013 at 15:18

Quote: Originally posted by Endimion17  
Why not using the search engine? This has been discussed ad nauseam.

Endimion17 is correct.

Why is anyone still replying to this thread? Please stop spoon feeding newbies who should be using the search function, you're just reinforcing the behavior.

Fantasma4500 - 3-6-2013 at 06:39

you should request ideas for specific compounds deposited on glassware in the sticky in misc. (which i happen to be OP of, yes im proud :D)
please take a look through at least all the sticky threads another time and try not to request spoonfeeding