I use Simple Green, works like a champ. You can find it at Costco and I have even seen it in grocery stores. Just spray it on and then wash, you can work it in if the blood is heavy but don't let it sit, maybe only as long as it takes the washer to fill, also don't wet it before hand or use any other remover prior, I found Simple Green wouldn't work then. We used to own a motel and this took blood out of everything.