If you don't mind looking at the skeleton you could leave it in there and wait they are known to produce buds from what seem's to be a dead organism(this could take some time though).
this is from wet web media,
>Things to look for in assessing the health of Open Brain specimens are the regularity and degree of expansion of their polyps, tissue pulling off the skeleton, and bleaching. If this occurs within a short period of time, it is likely that either some other stinging-celled animals influence or water quality are involved. Biomineral content (Calcium, Strontium, Magnesium) AND alkalinity need to be checked and if necessary, adjusted, and excess nutrient accumulation (nitrates, phosphates) guarded against.<
double check your water...