Depends on what kind of material it is made of, whether you can toss it in the washer. And if you do do this, maybe put it in a "lingerie" mesh bag first. **OH! But do NOT throw it in the dryer... dry it outside in the sun.
Try the "Mr. Clean- Magic Eraser." You can get it from any grocery store in the cleaning supplies aisle. This thing works on mostly anything, even marks on walls and carpets.
Or, try a toothbrush and literally scrub it off. Try apply a spray cleaner... or "upholstery" or "carpet" type cleaning sprays, and then let it sit, then use a brush to clean it off. But don't use anything with "clorox" in it or you will get "bleached" spots.
Or, try the kind of stain cleaning sprays for babies... the kind that removes vomit and poopoo and etc. There are enzymes in it that is supposed to remove blood, grass, mud etc.