Yes we see the mustard stain on your sleeve.
One of the biggest reason companies have gotten away from casual Fridays for their employees is people thinks it gives them the option to not get dressed for work. Casual Friday still mean you have to dress to interface with clients and co-workers. So put in a little effort dress up jeans & a tee shirt. Don't forget your blazer and your emergency pumps you never know when a client might need to see you or a staff meeting is called. You never want to be the girl in the sweatshirt because everyone will notice.