Have you tried the household stain-remover "Tech"? You can get it at some department stores and Ace Hardware. It is a non-toxic, non-staining, etc spot cleaner that works pretty well on fabrics. It is made by:

"TECH Enterprises, INC
901 Stewart Street
Madison, WI USA 53713"

After soap and water, I'd give Tech a try. The degreaser Goop may work, but I'd try a test patch first.

Hope this helps...Lee