In decorative painting, common uses are:

• A cleaning agent for brushes (use a cloth wet with acetone to clean dried paint).  Do not soak brushes in acetone for an extended period.  The solvent will eat away at synthetic fibers.  Always complete the cleaning process using soap and water.
• Preparing a surface.  Before priming certain smooth surfaces, like tile, metal, plastic, or lacquer, use acetone on a soft rag.
• Cleaning a surface:  Substrates that may be greasy or waxy, use acetone on a soft rag.