Media is cheap, your time isn't.
BTW, if you're not already, find a pet supply place and buy it in bulk from them. Much, much cheaper.
Past time for new. Way past.It's so dirty now that it leaves a plume of dust out the top if the lid is off and I sneeze and cough and taste metal if I am near it.
Time for new...
Well, why not?I was thinking of harder ways like tossing them in front of a box fan and sorting the wheat from chaff!