Cleaning Eudragit Tainted Glassware?

[Scottydog]

Swim got off his lazy ass and decided to FINALLY clean the eudragit "ring" that seemed to have permanently stained his 1000ml florence flask.

Up until now, the lazy bastard has just been shaking up the flask with hot water and then acetone and allowing to dry overnight. This has removed everything with the exception of the orangish, brown ring.

In other words, the last few months after having conquered the beast prior to rxn, Swim has been running clean feed in this tainted flask. Luckily enough, none of it has caused any problems in gakking up the most recent runs.

Swim tried a combo of bleach, baking soda and a bottle brush and everything came off with the exception of a "white salt-like stain"

Considering that newer pseudo extractions will now eliminate the yellow/orange oil, he has a feeling that he may not have to do a thorough cleaning again for quite awhile.

What have you guys found to work the best, what about this salt stain? I'm sure many of you can relate to this "ring"?

Swim hasn't "thoroughly" cleaned it in over a year.  

*******

Should have posted in Chemicals & Eqpt? If so, my apologies...

[evilscripter69]

works everytime

[MadMunkey]

sulfiric acid and h2o2 works great too(bee carfull)

[Rasputin]

Dear: MadMunkey
In your above post, you said to use a mixture of H2SO4 and H202.I am always looking for new(better?) ways to clean glassware.

What concentration of H2SO4 do you use?
What concentration of H202 do you use?
What ratio do you mix the two together?

Thank You

[hest]

70:30 Pirahna, take care not for kids

Post 459539

(NeoSynthesis: "Cleaning glassware - Practical Advise?", Newbee Forum)

[MadMunkey]

pour enough H2SO4(hardware store grade is fine) to cover the stain, or enough to work around the stain, and just a few drops of 50%H2O2. you gotta be carfull tho cuz H2O2 will start some nasty organic fires in high concentrations. also, if you add too much H2O2 to the H2SO4 it may blow up on you. remeber, just a few drops, till you see the H2O2 fizzing. let its sit for a while and rinse it real good. works for almost all non-organic stains and a lot of organic ones.

[armageddon]

try a strong solution of SnCl₂/HCl, and let that stand for some hours (or use a brush) - but be careful, the tin(2)chloride solution is one hell of a bleaching agent!!

Greetz A