The answer to 'how to clean grout yourself' is to use a grout brush, grout cleaning solution, and some elbow grease. Start by sweeping or vacuuming the grout to remove any loose dirt or debris. Then, mix a grout cleaning solution according to the product instructions and apply it to the grout lines. Use a grout brush to scrub the solution into the grout, working in small sections. Let the solution sit for the recommended time, then rinse the area with clean water. For tough stains or discoloration, you may need to let the solution sit for longer or repeat the process. Be sure to wear gloves and work in a well-ventilated area when using chemical cleaners.
Cleaning grout regularly, every 6-12 months, can help keep it looking its best. However, if the grout is severely damaged or discolored, you may need to have it professionally re-grouted or replaced.