Since ground-in dirt can wear away carpet fibers, your first line of defense should be your vacuum cleaner. Vacuum the entire carpet once a week; heavy traffic areas may need daily touch-ups. To clean up spills, various combinations of cleaning fluids, detergent, vinegar, rubbing alcohol, or ammonia may be recommended for different types of stains. Before using any type of solvent, be sure to test for discoloration on a matching swatch or inconspicuous area before applying. Spray-on carpet cleaners are sufficient for light soil, but occasionally you'll want to give your carpets a thorough cleaning. If you plan to do it yourself, there are three methods available, each of which has its advantages. Dry cleaning powders can be sprinkled on, then worked in with a special machine or brush. They absorb soil so it can be vacuumed away. Since there's no water involved, this is often the safest method for carpets. The second option is to use rug shampoo. This is worked into the carpet with a machine using rotating brushes. After it dries, you vacuum away the trapped dirt. This is an economical method, but sometimes leaves a residue that can attract dirt in the future. Finally, there's steam cleaning, which actually uses hot water rather than steam. The cleaning solution is injected into the carpet, then sucked back into the machine, along with dissolved dirt. This is probably the most thorough method of cleaning carpet, but overwetting could shrink or discolor the carpeting. You might consider hiring a reliable carpet cleaning service and letting professionals handle the job.