Hello! / Cleaning Oversized Glassware

Hi all. I’m new here. For my first of what i’m sure will be many questions, i’d like to ask if anybody knows of any tricks or pointers for the cleaning of large or awkward glassware.

I have a 50L rotovap round bottom flask, some 22L round bottom flasks. It’s a circus. I have no idea how to get in there to apply any scrubby brute force.

I used a base bath in he lab in grad school but I have nothing like that in my lab and fitting a 50L rotovap in a similar setup would require a kiddie pool!
Love the site.
I look forward to being of service and learning a ton.
BS Chemical engineering
MS Polymer Science
PS Not that it really matters.


Best is cip. Make up a long feed tube one that will touch the bottom of the flask. Add etoh through the feed tube, spin, heat,then suck the contents back up the feed tube into a carboy.a few rinses will get most stuff. Make sure the vacuum port at the top is open when you do this. Also call alconox up. They have great products that will cut tough resins.


What are you putting in your roto flask that burns on? Or perhaps, what are you using your roto for?

1 Like


Peep this post that talks about cleaning

1 Like

nothing burnt on per se, but the rotovap is just so big and unwieldy. and the 22L have such a narrow mouth that there’s just no way to get in there effectively. Roto is just for solvent recovery but multiple crude sources from CO2 and ethanol extractors plus ethanol reclaim from wax cakes. Since i’m juggling them it would be nice to clean it out. I do know about alconox thank god.

My question is also related to just getting everything out of a flask. If it was an ordinary shape you’d use a spatula. Somebody in industry has to have this all figured out by now. It’s been plaguing chemists for years.

and thank you.

Also, Future, the post you linked I think inspired my question. I saw it yesterday and forgot about it.
I just don’t know how to “touch” the sides of a 50L flask or a round bottom with a narrow neck. I don’t know of any mechanical device that allows that.

I’d like to stop short of Hydrofluoric acid if that’s possible. lol.


Ever see one if these?


hmm. yeah that’s not the least bit unsettling! ha ha. I guess it’s a start. I’m considering calling them to investigate and see it they’ve managed to sell any.

Air compressor + hand full of pieces of rag, Scotch pad, pick your abrasive + solvent

Air compressor is nice for drying glassware as well


I’ve had success cleaning large dirty flasks using the following method…
1.Nearly fill your 22l with hot water
2.Place flask on mantle
3.Turn on magnetic stir bar
4.Pour in 10g of sodium lauryl sulfate
5.Incubate ~10 minutes
6.Safety Meeting
7.Use a straight nylon brush with articulating head (option B is a 90° elbow nylon brush available at most brew supply shops)
8.Repeat until clean


Is this a gag item or is that a real thing?

It’s real, I bet it would be useful to harvest crystals or dryed powder from a rotoflask too.

1 Like

ACETONE! Its good for your health!

1 Like

Tell me more…

What do you want to know?

Once it’s empty, throw a couple of lbs of coarse magnesium sulfate in there with a little bit of warm Acetone (or if your crud is really baked on bad - some boiling hot limonene instead of acetone). Once you have this mixture in the flask, re-attach to roto and let spin on full RPM without vac. The course epsom salt rocks with act like a pumice to scrape crud off the walls. If your having trouble even with the pumice, u need to Spike the pH to either highly acidic (HCl) or highly alkaline (NaOH)


What’s your preferred mixer? I like 10% oj 90% acetone. …:stuck_out_tongue_winking_eye:

Lol ooo you are inquiring about the health advice not the cleaning haha. I am an acetone neat kinda guy with a few drops of strychnine synthesized by Woodward himself!


CIP??? What is that?

clean in place

1 Like