Is fully cleaning a molcajete even possible?

tldr: Can molcajetes actually be fully cleaned (if so how), or is minor residue normal and harmless?

Hi.

People often say to get "all" the gunk out. But from experience I do not see how this is possible without an absurd amount of time and effort if at all. I have yet to find someone addressing this issue satisfactorily anywhere online.

I've tried soaking with boiling water, power washing, and scrubbing vigorously with an escobeta as well as a finer bristle brush. I've even picked at individual bits with a tooth pick and pointy flosser to no avail. No matter what I do, tiny food particles remain deep in the crevices. So I'm looking for clarification.

For you molcajete users, is some tiny leftover residue inevitable, or is a full deep clean somehow possible? If so how?

Is this unsanitary/harmful? I cannot imagine why there wouldn't be mold/bacteria growth.

Do you ever sanitize it with heat or another method to prevent microbial growth? If so, how often and what’s your process?

For context, I have quality Molcajete (from Masienda). I cured it properly with rice then salt and garlic both of which I scrubbed out thoroughly (I believe rice is to used to dislodge loose debree not fill the pitting. Also rice spoils)