http://knittyblog.com/2017/09/the-sandwich-part-of-my-batts/
I love the newsletters I get from Strauch Fiber Equipment. They always lead me to such wonderful places. In this case the article points out, in a very quick way, a method of adding in extra materials into a batt, that goes through a drum carder, without getting extra things stuck in the drum carder. Great article!
Happy Crafting!