I would try to get anhydrous acetone if you could. And either fumaric acid or another acetone soluble acid such as citric, etc. As long as the salt of dmt from whatever acid you choose is not soluble in acetone it will work.
First weigh your fb to guestimate how much acid to use to salt it out of the acetone. No need for unnecessary waste. No more than 1:1 fb:acid ratio is necessary imo. Next dissolve your "dirty" fb in some acetone. After its done dissolving dissolve the same amount of acid in some acetone. Once it dissolves, (shake it and have patience), you can pour the acetone with the acid dissolved in it into your acetone with fb dissolved in it. This will cause your alkaoids to precipitate out of solution, leaving any oils or lighter residue in the acetone.
Decant and filter off your alkaloid salts, and preferably powder as fine as possible and do another acetone wash. This should get out 99% of lighter fluid impurities since the acetone will pull off the oils, and powdering your crystals before washing will ensures no impurities will get caught up in the crystal structure and end up in the final product.
Your done now if you want long term storage or pharma, if you wish to freebase, then you can use either sodium carbonate or koh/naoh to precipitate it out of water. Just dissolve salts in water, then koh/lye/sodium carbonate/potassium carbonate in water and add teh basic water into the dmt salt containing water. Freebase will precipitate out, koh/lye realatively quickly, and sod/pot carbonate rather slowly. After precipitation, you MUST wash with some sodium carbonate water, and for the last wash a straight water wash. No koh/lye/sod/pot carb needs to end up in your end product.
The other option is mixing a 1:1 ratio of lime/salts with just enough water to get it pastey. Mix well, let sit for an hr or two, then spread out and dry on a low heat source or no heat at all (recommended). Once its dry powder it well to increase surface area with the solvent, and dump it in some acetone.
Decant and filter if necessary, saving the acetone, evaporating to yield an amorphous freebase oil, that will crystallize upon scraping to leave crumbly white crystals that are very clean.