DIY Scent stations are a sensory learning experience to use for students with sensory processing difficulties. I have used a few different versions of this in my classroom. The fragrances can be changed and updated depending on the students likes / dislikes and what is available to the teacher.
I created a portable scent station for a student with autism who enjoyed smelling people and objects, however, was known to throw items regularly. They were to be used during her bus ride to and from the school as a fidget toy. Therefore, I used bath scrunchies and sprayed them with different scents. This way, if they were thrown, they would not damage the bus, or hurt anyone on it. They provided both stimulation for her senses as well as a distraction as a fidget toy.
This scent station activity is more for use in the classroom, possibly as a work task. I avoided using glass jars (as this is generally not safe in any special needs classroom), and invested in a magnetic spice rack. They provide both a visual window and holes in the side to smell the scent. The lid can be easily removed for a more intense smell.