I agree with arcologist, but I would say that I actually think a lot of the smell is related to residue solvent, since when redissolving in ethanol or acetone and reevaporating fully, smell diminishes. Also when precipitating DMT freebase from water like the BLAB tek conversion, the smell is a bit more neutral, flowery-crayon, instead of too sharp and plasticky like from naphtha crystals.