I usually just let it soak in acetone and try to clean it with a brush.
I don’t really get it that clean.
What’s the best method to clean your boiling flask for your spd?
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After a run (once it has cooled sufficiently), I pour acetone or isopropyl into the flask and then heat to 80C and let spin at 600 RPM. I keep everything connected except for the collection flasks. The solvent will bounce around the flask and the vapor will travel through the system and clean it. I keep a jar at the end of my cow to collect the solvent for future use. Once that seems to be clean enougy, I dismantle it and then introduce more solvent to the flask and swirl it around. I also use a stainless steel wire to “scrape” the sides to remove any carbon/clay or tails that may be stuck. Then continue to swirl solvent until clean. Final rinse is always done with acetone.
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This may help
And they couple links in this one too
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Use your SPD to distill the solvent but without vacuum. Disconnect the vaccum hose. I use methanol or isopropyl. At some point the boiling flask will be all dissolved, plus your rig will be pretty clean this way too. Then pour off the liquid. I always plan a solvent run even in my sublimator after a run just to clean. It still takes a brush and physical wipe to fully clean all parts but not so bad.
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I like the approach shared by @23extracts…
…but still haven’t talked the boss in to handing over the kiln that’s been sitting in his shop, unused, for the last five years.
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It sounds silly but a good amount of sugar and a small amount of water usually does the trick for me. Place a whole bunch of sugar into the flask, add enough water so that it starts to firm up and clump a bit (but not enough that it is runny) then just work the wrist and swirl it around for a while. You may need to change out the sugar once it gets dark or starts to really clump. At that point just add excess warm water to dissolve, empty the flask, and add fresh sugar.
No magic chemistry in this process. Wet sugar is just a decent abrasive that is easy to get into and out of a flask! I do this whenever I burn something onto a flask and a brush just isn’t doing the job. I had one that I really burned an oil onto the other day (walked away from my decarb). I scrubbed and scrubbed with my brush but I couldn’t get mess off. A little bit of sugar, some water, and about 20 minutes of swirling layer she was clean as the day she was made!
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I like it. similar to using NaCl, but without the “salting the earth” disposal issues.
should work for lowering the temp of an ice bath too if I remember the explanation for why that happens correctly. although I guess most folks have moved to dry ice slurries or circulating baths for their hydrocarbon cooling needs these days.
Edit: instead of throwing out the sugared water after use, ferment, then distil to 190 
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What’s everyone’s method of drying said glass pieces after cleaning?
Do most of you have a rack, lay on a table, etc?
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I do the add iso during cool down after run immediately and it won’t leave the funk … after I definitely have a good alcohol soak and then a hot rinse cycle in a proper machine … I take glass out still slightly wet and blast it with air , I have a small 100 psi pump with runner tipped hose that is perfect for this … no spots , no funk , no problem
I bought a baby bottle dryer rack from target and it works like a champ lol.
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Try limonene! It will work much better than almost every other solvent available and is safe to use. I just add really coarse salt to the flask and a little limonene (only enough to make it a slurry) and then swish it around and heat with a heat guns as needed.
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Yep, Limonene is definitely in my cleaning tool kit.
I’m guessing one could substitute sugar here as well…
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sure could
https://www.thomassci.com/Laboratory-Supplies/Brushes/_/Volumetric-Flask-Brushes1?q=flask%20brush
I got a couple of these for 1 L and 3 L pear shaped flasks and they work like a champ. Rinse, scrub, rinse again with your solvent and done.
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Limonene is my best friend when it comes to cleaning ye old boiling flask. I let the flask cool to a safe temp, dump out as much gunk as possible then put back in the mantel. Add 2 table spoons of 100% Limonene and spin up the stir bar. Dump and repeat. Works like a charm!!
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Acetone reflux, then limonene reflux (heptane/hexane would work too). One polar, one nonpolar. Salt in the flask and high stir speed.
If there is still gunk (there really shouldn’t be) try an acidic solution (either aqueous or in nonpolar solvent)
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I’ve recently been using sand box sand and limonene for my funked up flasks. Works miracles.
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I sprayed my flasks full of heavy duty oven cleaner and left them to sit for a few days, wore an O vapor mask to clean and it came out clean.
DCM would probs do a great job too, a jug of kleen strip should do the trick. its a blend of DCM and methanol.
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Acetone then zep degreaser takes off most everything.
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