Scrape the dish, crumble the extract/turn over and let it evaporate even more. There will be still some solvent left.
DMT has a 'plastic like' (moth balls) kind of smell. Some people may describe it somewhat different (fruity?) but for most moth balls type of smell is right on point. DMT smells exactly like my grandma's wardrobe when I was a kid.
Be inquisitive and always question things...