Saddle blankets, pads and turn-out rugs, coolers and other non-leather horse wear can get very dirty, very quickly. Manure stains, arena dust, mud and other grime can build up in the normal course of wear. You can chose to send your gear out to a cleaning service where they will clean and do any mending that needs to be done. This is perhaps the most costly route. The benefit is that they will have heavy-duty industrial sewing machines and materials, and large capacity washers that are far more sturdy than anything most of us have for DIY repairs and cleaning. Getting your gear cleaned is a simple as dropping off your stuff and picking it up when it's done.
I tend to be a DIYer for most of my repairs and cleaning. I know from experience that washing heavy turn-out rugs in either a top or front load washing machine isn't really recommended. Even extra capacity home machines aren't large enough to handle these blankets, especially after they've been saturated with water. Plus the hair that inevitably sticks to the blankets and pads are difficult to wash out and over time can clog up pumps and filters. It also makes a mess of the machine and anyone who does a white wash load after a horse blanket (or a dark load, especially after a white horse's blanket) may be a little frustrated.
Lighter blankets like coolers and sheets can be machine washed, but they still make a mess of the machine. Wash them one at a time and you can wrap socks around any metal fittings if you're worried that the tub will become scratched. I've put lighter blankets in the dryer, but again, the hair can make a mess and if you don't wrap the metal fittings and the clanking and clunking sounds awful and probably isn't good for the drum (I make sure my husband isn't home to hear). Instead, line dry them either indoors or out.
The most effective way we've found to clean blankets is outdoors with a pressure washer . Choose a warm day that is good for playing outdoors in the sprinkler—you're probably going to get a little wet. Pick a spot on your lawn that needs watering. To wash pads, put them over the back of a sturdy garden chair after you've dunked them in a tub of slightly soapy water (livestock soap is handy for this). Start from the top of the pad and work your way down. My husband recommends the spiral spray pattern. This will carry the hair and dirt downwards and by the time you've reached the bottom edge of the pad the water should be running almost clear. Turn the pad around and work down the other side. Flip the pad over, and do both sides.
For heavy turn-out rugs you may want to lay them flat and brush or sweep the excess hair and loose dirt off before washing them. Take the garden hose and use a car brush or broom dipped in a bucket of slightly soapy water to scrub both sides of the blanket. Really manure crusted areas may need some extra scrubbing or soaking time. Do both sides, inside and out. With the pressure washer, start from the middle and work your way to the bottom edges with the spray, because the bottom edges are usually the most soiled and you don't want to drive the dirt upwards on to the cleaner areas. Flip the blanket over and do the other side.
If it's a nice sunny dry day, you can leave the blanket a bit so the water will drain out and it will be lighter to pick up and hang. A saturated turn-out rug can get really heavy! But hang it to dry as you won't want to cram a heavy rug in your dryer. If you don't have a pressure washer, use the garden hose to rinse, rinse, rinse until the water running from the blanket looks clean.
After the rug is completely dry you may wish to re-waterproof it with an appropriate spray. Check with the manufacturer for recommended products. If it's time to pack away your rug for the summer, fold it so it's easy to put on your horse next season. Some people like to pack cedar blocks or shavings, or moth balls in with their blankets. Mine hang on a hook in the garage until it's needed again in the fall.