I throw my saddle pads(english) and stable sheets in the washer. I have done them in a top load with no problem. They don't seem to look clean though until they run through the dryer. Once I pull them out of the dryer they are spotless. I just make sure I spread the saddle pads out evenly in the top load and they seem to run just fine.
Do not use fabric softener though. When I am done I run an empty cycle through the washer and it cleans it just fine. I don't see it being any different then doing my barn clothes really.
My blankets I do at the laundry mat... oops was there a sign there that said no horse blankets? I never saw that
I just do it when no one is around and then I will wipe out the washer to make sure its clean.