Before starting work, it is advisable to protect the table (or other surface) with a cloth or with sheets of newspaper. It is advisable to choose a properly lit floor. Then the jar is carefully washed; if you decide to use it for other foods it is preferable to sterilize it by boiling it in water for about 10 minutes. To paint the jar, a “low-tack” ribbon ring must be applied inside, about 2 cm from the opening. In this way it is a guide for the application of colors. An idea can be to apply some stencils to get a more precise design.