The result looks like a goo because of impurities from the plant (such as plant oils and fats) and/or the reagents and solvents (such as NaOH) used in the extraction. It still contains the DMT however, all you have to do is to clean it. Dirty spice can be cleaned by dissolving a small amount of sodium carbonate in water, dissolving the impure goo in clean naphtha, and then combining these two and mixing. Most of the impurities should then move over to the water+sodium carbonate layer, whereas most of the DMT will stay with the naphtha. Repeat if necessary.
A contribution to avoiding this problem in the future is to not evaporate the solvent, but rather freeze a container with the solvent. As DMT isn't really soluble in freezing cold naphtha, the DMT will crash out of the solution given a few hours, forming crystals on the bottom and the sides of the glass. The glass is then scraped, and the contents are poured out through a coffee filter. This way the crystals stay in the filter and the naphtha can be reused. Note however that the naphtha now contains impurities, so you can't reuse it indefinitely.
The reasoning behind this is partly because naphtha does indeed pull some impurities that will stay with the solvent even when it's freezing, and partly because it is much more economically and environmental friendly. Recrystallization may also be a good idea if the DMT still looks impure. For more information, search our forums and our wiki.
Hope this helps! Safe travels.
