one of my girls has a white one. Not a stain on him. She picks the pen just like I use to do daily with horses stalls. That's number one. We bed with straw. Dark mulch will stain their knees. Getting up and down. For washing we use any purple shampoo that's cheap at Sally's Beauty Supply or Walmart. For stains and yellowing we use liquid Oxy-Clean, spray and leave set for a few.