There is a groove running around the top inside that needs to "snap" over the raised glass ridge on the Mason jar (just under the threads).
Remove the sleeve by holding the jar by the threads and pulling on the hole in the bottom.
When I need a little extra coffee, I go for a pint & half jar. My silicone sleeve keeps my hands safe, and if I need to leave the house I screw on a wide mouth silicone drinking lid.
Microwave safe means you can heat up your beverage without removing the sleeve. Or take out a frozen jar of food, put a sleeve on it, and heat it up.
Since they don't touch your beverage, I often just rinse them, but they are also dishwasher safe. You can leave them on the jar, but I find that water gets trapped so I prefer to separate them to clean the jar.
You could also use one to block sunlight or prying eyes from the contents of your jar.
Great for kids and adults!
