Just asking if it is ok for a small amount of MHRB gunk spilled into an evap dish? SWIM knows it won't evaporate but is it possible to remove it from the evap dish easily enough or is it ok to leave it in? Would it make much difference if someone were to smoke the crystals? Thanks

Best, safest, wisest way around this is wait for the solvent to completely evap and perform a recrystalization. That should suffice to separate the polar bits away.

I found acetone wash to be the quickest way to separate any residual impurities/bark. It's super easy to evaporate after all is done. You can also use heptane/naphta. Add the solvent, mix and let the impurities rest at the bottom. Decant and evaporate the solvent and you're good.

Acetone is a polar solvent and will most definitely dissolve the polar impurities too. That’s not good cleanup practice afaik. Use non polar solvents. If heptane is hard to come by just use naptha... most of it is heptane anyway.

Acetone is actually both polar and non-polar. If NaOH was used then acetone wash will get rid of it as NaOH doesn't dissolve at all in acetone. Acetone also won't dissolve any big leftover particulate from MHRB, hence you can decant. NaOH is the big baddie that you definitely want to get rid of. Big advantage is that Acetone is super easy to get high purity, it's also quick and easy to work with.

Heptane will def be better as it's strictly non-polar but not as easy to get high purity and takes longer to evaporate. Naphtha can be mostly heptane but it could be 100s of other compounds as well.

Actually for the present purpose acetone will stay a polar solvent. Unless 100% anhidrous or pure, which either way will be definitely harder to come by, or at least harder than sourcing some good ‘ole nps, acetone will retain water thus the risk of base being soluble in it exists. Whereas nps does not pose such risks, does not contain or abasorb water from the atmosphere and it definitely has the advantage of xtal formation over any other type of polar solvent.. which would certainly render a goo..

As for naptha, no, it will not contain 100s of compounds. Who told ya that? It will otoh contain a mix of 2-3 hydrocarbons of 5 to 7 or even 8 carbon atom chains.

I myself use analytical grade of acetone. True it's not as good as for ex heptane for DMT crystallization but it's very easy to work with and comes in handy in many situations.

Yes, Naphtha can be 100s of different compounds. It can be crude oil, kerosene and even mineral spirits. It can be a mixture of several hydrocarbons plus multiple impurities. All depends on the manufacturer and even region. In general you can never know for sure what is in your naphtha.

Who told me that? My chemistry professor while I was sitting for hundreds of hours in a chem lab :-P

Ps. I meant 100s of compounds in general, not in a single batch of naphtha. English be hard ;-)

I hate to be the one that hijacks the OP. Sorry for that!
There will always be more room to support or negate various chem related assertions, especially on this subject. I do feel that there is solid advise here already. I’ve upvoted for you, atomu235.

Thanks Lumina :-)

Nothing beats a good conversation. Always question things :-)

OP, to avoid this problem in future, always transfer your NPS via an intermediate container (e.g., a Pyrex jug) before it enters the crystallisation dish. That way any contaminating goo will be caught.

Simple, immediate solution - transfer solvent to a new, clean dish while taking care to ensure that the gunk gets left behind.