Carbon Filter Operated
Many models are made with a base that includes a carbon filter. When the cigarette is on the base, the machinery works to draw the smoke into the base compartment, where the smoke is somewhat "purified" by the carbon filter.
Some smokeless ashtrays feature an ionic system. Many of the manufacturers claim this to be the best and most advanced system.
Some even claim that it eliminates secondhand smoke from the room by breaking down the smoke particles and circulating clean air back into the room. The ionic ashtrays also eliminate the need to repurchase and replace filters.
There are even models that can be hooked up to a USB port on a computer instead of using batteries.
Some larger models allow the smoker to snuff out the butt of the cigarette or cigar into a lower compartment. This is claimed to reduce the amount of continuous smoke that is emitted into the air.