Method
1. DIY stores often sell small sample-size containers of paint. This is an inexpensive way to get a wide variety of colours for this project, as you do not need much paint for each jar. Pour a small amount of paint into a clean glass jar.
2. Coat the inside of the jar by tilting it to move the paint around as you cover the inside. Add more paint as needed.
3. When the inside is fully coated, carefully pour out any excess paint and wipe the rim and outside of the jar clean. Let dry. This may take a day or two.