If you look at the care instructions on saddlecloths there are actually quite a few that are hand wash only, please check the instruction before washing, as things like water temperature and how they are dried can cause problems to the shape of the saddlecloths.
When washing mine in the past i have found that the thicker, puffer ones such as Eskadron big squares and PS of Sweden have been fine going straight into the machine and washing well, they come out very clean. However with some of the thinner, stiffer ones like Le Mieux i have found that i have needed to give them a good scrub by hand first. I do this in the bath with a dandy brush, and then put them through the machine. I have also found they wash best if i only put one in at a time.
If you have a particularly dirty saddlecloth, or one that has gone mouldy pressure washing is a really effective, and satisfying way of washing them clean again, you can also pop through the washing machine with something like vanish or napisan afterwards to really get them sparkling.
In order to protect your machine and stop all the dust, dirt and hair getting into your washing machine you can buy wash bags to put the saddlecloths in whilst washing. These are a really good idea and they work really well, it also saves you having to wash out the machine and run it on a cleaning wash afterwards as well. We have a selection of washing bags here.
Most rug washes will also wash saddlecloths for you from as little as £2 per cloth. So if you have a large collection you can wait until a few need washing and then send them all off together.
When drying the saddlecloths it is best to hang them over a chair away from radiators and out of direct sunlight and let them dry naturally, most dry quite quickly and are ready to use in no time.
If you have a wool saddlecloth you are washing make sure you use the correct detergent for them, many of them come with a small bottle free, and you can buy bigger bottles from the tack shop or online. Wool saddlecloths should be laid out flat, wool side up to dry, and they given a brush over when fully dry to put the fluffiness back into the wool.
If you have a corrective saddlecloth with shims, be sure to remove the shims n=before washing.
Most gel pads can washed in a bucket of warm soapy water and rinsed off and left to dry, If you gel pad is loosing its stickiness then it is time for a wash, and it will become sticky again. Some gel pads are also suitable for machine washing.
Be sure to check your saddlecloth after each use to see if it needs washing, if it looks clean and your horse did not really sweat it should be good for another use before washing. However during summer month or if your horse has sweated then they will need washing before using again. Be sure to check the back hem of the saddlecloths to make sure these are getting clean int he wash, as dirt and scurf can build up here and go stiff, which in turn can lead to the saddlecloth rubbing your horse. Yo can also give your saddlecloths a good brush with a stiff brush in between uses to lift off dirt and dust etc.
Keep an eye on your horse to make sure they do not have a reaction to any of the washing products you are using. You can buy special saddlecloth wash from tack shops, or you can use baby washing detergent, however it really is trial and error to see if there is any reaction.