Very Effective
Long ago my father told me that if he was driving and began to feel sleepy that he would take a whiff of smelling salts to regain his alertness.  I have used his suggestion many times over the years.  Recently I have been unable to find smelling salts in retail pharmacies, so I was delighted to see that they are available from amazon.com.  MacKenzies smelling salts are perfect for the use I make of them.  They are sufficiently strong and there is no liquid in the bottle, so there is no chance of spills.
Rating: 5 stars