Rejuvenating media is a wives tale. Buy media in bulk. All you are doing is trying to polish turd!
And, just throw it away.
Corncob blasting media 14/20 grit from Graingers or McMaster Carr
Lizard Litter @ Pet Smart etc is ground walnut shells.
Nufinish works well.
But, IMHO
Iosso
Flitz
Dillon
do a better job.