hydrating cakes

I have been serching for ways to keep cakes hydrated to make them last longer.  I have not found anything on this but I was wondering if anyone has tried this.  While loading the jars with substrait Placing a small square or any shape that fits into the center of the jar and finish filling with brf/verm mix just like pf tec.  after birthing cakes and dunking over night the sponge will hold extra water for a longer period.  After each flush injecting the sponge with spring water instead of redunking and rolling in verm.  so instead of using a straw resevor or any other thing like that use a sponge.  I would live to know if anyone has tried this and if they had any luck.  would this make it easyer to contaminate.  does anyonw see a problem with trying this because I am going to run an experiment next time I make cakes and try it.  I will post results.