For tank types, if you notice a burned taste after turning up your twist or Vamo type, turn it down and dry vape while not pushing the fire button, this will flood the wicks with fresh juice and will most times eliminate the burnt taste.
If you let the burnt tasting atomizer wicks, (they are not really burnt, just have carmelized juice clinging to the coil), steep in the juice without doing a dry vape they will infuse the entire tank full, (like brewing bad tea) and you'll have to throw out the whole works.
Sometimes letting burnt tasting juice sit poured back into a spare bottle will mellow the burnt taste and make it useable again, often times not. You can tell by giving it a wiff or two in a week.