I use that exact stuff. I store mine in a deep freezer at work for a few weeks before use. Once it thaws I keep in in a rubbermaid under his tank, I stir it every other day or so as it dries just to help prevent any mildew and make sure its all aired out.
I know that you were just asking about mulch, but here are some tips of what works for me for cleaning/treating other decor too
For new logs/rocks/branches that I find or buy I toss them in the tub and submerge for 24-48 hours then allow to air dry for several weeks (in the case of wood - while watching for mold). To disinfect my terra cotta hides, water dish, rocks, and non-plastic decor I put it in a 5 gal metal bucket and pour boiling water over it and let it soak until cool enough to take out. The cage itself is disinfected with diluted chlorhexidine and rinsed well after I vacuum all the mulch dust out as needed. I spot clean daily - he likes to crawl through the water dish and make the mulch under it wet as well as drag chips into it in his midnight travels :/
hope this helps
I read this article by VPI (© 2006, Vida Preciosa International, Inc.) and it explained a lot about snake mites. http://vpi.com/publications/the_life_history_of_snake_mites