I purchased some "vintage" lace and trimmings at a yard sale and incorporated them into some wet felting to cut into heart shapes for Valentines! (See my entry on the process of wet felting). Now, lace and other non-wool textiles will not easily felt (that is, they will not "lock in" to the wool base) unless they are applied near the end of layering for wet felting, and covered with a thin "web" of wool roving. Even so, the non-wool fiber scraps should be needle felted into place if you are going to use the resulting fabric for some application that will need to endure lots of wear and tear. But, for a greeting card, no problem!