Yeah, would not put water soaked meerschaum in a 300 deg F oven: it is an extremely porous material and if there's any differential moisture in the pipes it may easily crack. Can't speak from experience though: I've never had to clean any of mine because I bought mine new. Maybe it would work OK.
If it were me, I would try filling the bowls with activated carbon (or any type of charcoal, really), saturate the carbon with high test potable alcohol for a few days, then knock out, rinse with distilled water, and let dry completely for several months or more.