If you follow the storage conditions, then nothing will happen to the contents of the jar. You can not be stored in the heat for a long time and fill with water. If you have not used incense for a long time, it may seem that it is exhaled and does not smell. In this case, remove the top layer, this should help. In the same way, you can solve the problem with droplets on the surface. The rancid smell speaks about the unsuitability of the fragrance. If it appeared, something happened to the essential oils.