Tide pods. Tide pods. Tide pods. They work the best. The only thing that they have not taken out was 3 week old mud!
Soaking over night with baking soda I hear works well
Chlorox color friendly stain remover
Soak it in dawn dish soap overnight and then power wash it.
Power washer works wonders
White vinegar is your friend! 3 washes and let soak!
Try soaking a few hours in oxy clean then put in the washing machine with more oxy clean