Make sure your jars are clean and dry to start.

At any height on your jars, place a strip of masking tape on either side of the area you wish to paint on your jar. Make sure the strip overlaps itself so that you have a nice even line with no gaps for the paint to run in to. Gently press down on the tape all the way around the jar to rid any air bubbles that may appear.

Using your large paintbrush, coat the area with a generous first coat of blackboard paint, painting consistently in one stroke around the jar. Turn the jar as you paint to achieve this. It may look streaky and this is okay as you are going to give it a second coat. Wait about an hour to paint your second coat.

After an hour has passed it is time to coat your jar again a second time with the blackboard paint. This should alleviate the streaky look. This time leave the paint to dry overnight.

Slowly peel the masking tape from the jars to leave a smooth and even strip of paint upon which to write. If the paint strip looks uneven and ragged, it can be made smooth again by the use of a scraping instrument / sand paper. Label your jars as you wish for keeping things organised in and around your workspace.

Enjoy your neat and tidy workspace!