lots of things can be used to swish. the thing to do is experiment and find out what it does for you.

I don't know that it is necessary to pull with charcoal like you do oil, since one oil pulls for 20 minutes. I and some others I know use activated charcoal powder to brush teeth with and it seems to absorb any undesirables in just the few minutes it takes to brush one's teeth. In addition, if you have gingivitis or receding gums or loose gums, they seem to resolve when brushing with charcoal over the course of a few weeks, just like they do with oil pulling. Charcoal powder also whitens the teeth nicely (and faster than oil pulling does). But, it makes a mess in the bathroom sink necessitating cleaning it every time you brush with the charcoal. =(

The thing that oil pulling does is provide a like solvent for the fat soluable toxins circulating in the lymph and blood stream systems. Charcoal absorbs a lot of different things (and there are some things it won't absorb), but I don't know if it will absorb / draw toxins from the saliva like oil pulling is reported to do. It may just clean up your mouth.