In general, the smoke usally gets turned off by a switch somewhere or in the command settings. Not all units have a shut off. (but count me as mth weak) Adding one is likely an option if it doesnt have one. I would have to assume that tender dial is a manual volume knob. (but ASSuMEd)
If you tend to ignore filling them, the burnt wicking isn't all that will suffer. The fluid also keeps the element cool enough to not burn up. Less cooling action= a shorter life. Old post war was nichrome wire wrapped on a ceramic 'disc'. The ceramic kept the wire cooler if dry so those lasted without an off switch.
You could try some acetone on the char. New elements aren't very costly, packing is real cheap. Even the mfgs offer a few different packings. All work best for different folks opinions . Home brew wicking varies from pink household fiberglass to oil lamp wicks with results a variable.
Any char will slow wicking, char on the element will shorten that wire life reataining more heat too. But most will get charred wick over time. Expect to deal with it from time to time, hot rodded smoke units more so...but what a gain