Does anyone know how to disinfect a sea sponge so that it is fit for facial use?

I would add a little bleach to the water and soak it for a bit, then rinse it well. Maybe 1 part bleach to 10 parts water.

Best way to clean a sea spong is to use vinegar.
Pour vinegar into a bowl that is slightly larger than your sea sponge (Vinegar is a natural cleaner that will cleanse and deodorize at the same time)
Add warm water to the vinegar until the bowl is almost full. Stir to mix the two ingredients.
Place the sea sponge in the bowl and give it a squeeze or two so the vinegar water will be absorbed into the sponge. Leave for two hours.
Remove the sea sponge and squeeze it a few times to wring out the vinegar water . You do not need to rinse it out. Just set it out to dry naturally.

I’ve also heard that getting it wet, and putting it in the microwave for a minute or so will kill any harmful bacteria.

Do not put bleach on a natural sponge. It will disintegrate.

Vinegar and hot water but I’m not sure how long to keep the sponge emerged. Perhaps a few hours to be sure. Boiling or baking it would work too.. but I’m not sure how baking would work with a sponge or just how dirty it is. I use a lot of alcohol to disinfect things quickly when I’m cleaning packaging to fill with creams or scrubs. Perhaps a final dip in alcohol might disinfect the thing completely after boiling.

Thanx you guys! :)

What about alcohol? not from a liquor store, but a bottle of rubbing alcohol? would soaking the sponge in alcohol disinfect it or would the sponge also disintigrate, as with bleach?

I would clean it with an anit-bactiral agent, and after use be sure to let it dry out as germs breed in moist conditions which in turn will likely cause pimples if you smear bactieria on your face.