Don't do what I did to my first Evod, which was try and pull out the main wick from the coil, with the results being destroying the coil, LOL! It did, however lead me to learning to wrap coils and my current arsenal of rebuildables, LOL!
You can 'dry burn' to get gunk off of the coils and wick as well as soaking in vodka, but please insure the vodka is evaporated first. There are plenty of videos posted about how to do it.
I have a coffee e-liquid (Cafe de Leche from Nashville Vapor) that requires a dry burn every tank full in order to maintain vapor and flavor, the darker stuff gunks up coils and wicks fairly quickly.