Burnt taste is usually from too high of setting on a VV or needing a new head. The coils get a buildup over time, will taste bad, and may even irritate your throat or sinuses.
An alternative to replacing the head is to "dry burn" to remove the buildup.
I have to burn my nova off every week to prevent a burnt taste. Been using the same coil for months.
-remove the clearo and empty it
-rinse it out with water
-unscrew the tank from the base
-lift off the soft plastic piece from the head(where the wick goes in)
-rinse the inside of the head and wicks, gentle with the wicks
-blot the wicks semi-dry with a paper towel (again, gently)
-put it back on the battery
-fire it until the smoke stops coming off it. you'll have to do it in bursts to keep the battery from shutting off. the coil will glow red
-remove it from the battery, let it cool for a few minutes
-rinse and blot dry again
-reassemble
It's ready to go and should taste like new again (It will take a few puffs to dry the water). Sounds like a lot but it only takes a couple of minutes.
If the wick is fouled (black after burning it off and rinsing) there's not really much you can do. It won't wick as well because It's clogged.
Soaking it in vodka will help but it's a lot of trouble, so I just replace it at that point.