I vacuum off shedding hair. I put one pad at a time in, folded horse side out. I use a large load of hot water in my top loader and soak for a while to loosen gunge. Then wash on regular and hang dry.
I wash more often in the summer, as they pads sweat through. On a camping trip I try to take one pad for each day as they get super sweaty and I don’t want any irritation on multiple days of long back country rides.
But I also go for darker colors. If I had a nice white pad I would save it for shows not even lessons. Also I’m not sure about white, but my Ogilvy and LeMieux pads all have black backing regardless of the pad color.
I really like the look of dark piping on a white saddle pad to give it some shape but I think if I bought a nice white pad I would get no colored piping so I could use Oxyclean without qualms. Oxyclean solution kept wet out in the sunshine is quite effective on stains on white.
I do have some imperfect white pads I collected just in case I suddenly need to be presentable but the stains under saddle and bottom are kind of stuck there. I did bleach them