Dont use baking soda as it will be transferred to the snakes. Imitation Vanilla may work one one or 2 mice, but get a lot and adding to water systems will just be a bacteria nightmare.

Use Pine Pellets and change often. 3 times a day i open window and vent it out for 10 mins at time. Cant go too long as snakes are in same room and dont want it to cool too much.