If your home's exterior is starting to look grungy, it may be time for a power wash treatment to clean the siding. Whether you have aluminum, vinyl, or another type of siding for your house, it needs to be cleaned from time to time to remove mud, mildew, and any possible mold that is growing in niches or on the surface.

Things that can add to your home's dirty siding including bird droppings, especially if they nest under the eaves of the house or in your attic. Insect invasions, like ants or bees, will need to cleared out. Follow the directions on an insect repellent can or call an exterminator for advice. It's important to get rid of these pests before washing the siding, or you could get badly stung. Scrapes from cars or bicycles, along with other outdoor toys, should be wiped clear or fixed, if necessary. Then you will be ready to clean the siding.

The best way to clean your siding is by renting a power wash system that attaches to your garden hose and creates a jet spray that loosens dirt and debris from the surface and forces it to the ground. Most tool rental stores offer this equipment at an affordable rental price. After hooking it up and adjusting the water spray, start at the top of your house, just below the roof, and work you way down, level by level, until you reach the bottom, thoroughly spraying each section to remove streaks of dirt. If your siding is muddy or very dirty, try adding a teaspoon of trisodium phosphate to each gallon of water for increased cleansing action. Begin spraying from the bottom up when using the cleanser, and then go over the same area, level by level, as you work your way back down to the ground with a clear water rinse.

You may need to use a wire brush to scrape away burns, bird droppings, cobwebs, or other stains and debris before washing the siding. While you're at it, look for evidence of mildew or mold. You can treat these with laundry bleach, although check a small area first to be sure it doesn't change the color of your siding. Trim away brush from the siding so you can work close to it, and this will also keep the brush from hugging the house and encouraging insect or rodent nesting.

While you're at it, inspect the siding for signs of chipping, cracking, breaking, or crumbling. If you have spare siding available and know how, you can try replacing the damaged pieces yourself. If not, call an expert siding repairperson that can fix the broken areas for you to make your home look almost as good as new. Plan on power washing the exterior once or twice a year to keep the siding in good shape. If you're not sure about how to use a power washer, you can pay someone to do this chore for you. Check his or her credentials through the Better Business Bureau, and ask for references, first.