If you don't dry shellite recovered alkaloids really well they can be really nasty and make you feel super sick even for days if you consume them. Poison.

Single drops do just fine on the evap test on every batch of shellite I've used. It does tend to be slightly endothermic on evaporation though so if your environment is humid you may see condensation but I have not seen oils or other residues that won't evaporate.

All that said it is a hydrocarbon product and it doesn't ever claim to be food safe.  , so it's important to test every bottle you get, it may not be the same quality as the previous.