Throw out all the substrate and use paper towels while treating. You can bake the wood but make sure it doesnt catch of fire lol. I would take everything else out and put it in zip lock bags and shoot a shot of PAM into the bag and seal it and put it out of the deck for a couple months while treating the snake. That includes gauges and any cage accessories except hides unless the hides are complex ones with nooks and crannies. If they are the plain black plastic ones like RBI or Bean Farm, then you can leave those in the cage while you do a spraying. Just make sure they are dry before putting the snake back in.

I wouldnt use bleach unless you are worried about crypto or some other disease. Just spray it with PAM and cover it and let the PAM mist soak into the cage. Do that once every 5-7 days for 3 months as well as changing out the paper towels with fresh sprayed ones.

Remember, a little PAM goes a long way so you dont need to drown the cage in it.

And i personally never used Reptile Relief or any of that stuff as my belief is if it designed to kill mites, it IS a poison and i dont want to be rubbing my snake down with poison.

Also one last thought is if you dont want to use a chemical, you can order predatory mites called Hypoaspis miles mites or in europe, called Taurrus mites. They will eat snake mite adults, eggs and larvae and then if no food is left, they just die off.