coke problems - odd cut preventing conversion

[superman]

i took some coke freebase, placed in spoon, added 5% acetic acid and dissolved what i could.   there was this oil that will not dissolve though.  upon separation it looks like crack but has little effect upon smoking (i suspect this is lidocaine).  upon removal of this oil from the acid solution i tried to evaporate to dry but there is still an oild which will not dry.   what may this be???   how can i dry this coke out???   this was only i tester, i have a fair bit i want to revert to coke but obviosly not until i figure out how to fix this.

would love some input