Like others...having a hard time finding 99% locally. What are the disadvantages...other junk in the changa?

i would like to know about this as well actually. i don't think there would be any "gunk" as the other 9% in the IPA would be water. i would assume it should work fine, though a little slower, but i would wait for our nexus experts to answer this

Works absolutely perfectly

you can take magnesium sulphate (epsom salt) and throw it in the microwave for several minutes to get all of the water out of it. you will then have anhydrous magnesium sulphate which you can put in your 91% ipa, shake, and filter, to leave you with higher purity ipa. You could figure out exactly how much would be needed ideally by calculating the moles of water in your ipa. Each mole of mgso4 will take on 7 moles of h2o if i remember correctly. good luck.

91% or even lower would be fine. More water just means longer evaporation time.

if its 91% and the 9% is just water, and you are dissolving pure freebase dmt, its fine, it will just take a little while longer to evaporate.

If there is more than just water in those 9%, thats not good. Or if you are trying to use the IPA to pull from, say, a mix of sodium carbonate+dmtfumarate or acetate that was freebased, than it will be a problem because the 9% water will pull some sodium carbonate and sodium fumarate (or sodium acetate) impurities.