I was told this little trick a while ago and it does work, sounds wierd but it works. Use brake cleaner, but DO NOT GET IT ON VINYL PARTS, IT WILL REMOVE THE PAINT! It doesn't hurt or stain the carpet though

and when it removed the stain, it doesn't leave a ring, amazing. The smell is pretty strong so your going to want to clean the area, after it dries, with a good carpet cleaner and let dry with the windows down if its too strong for you. Good luck