I've been watching some youtube videos and I want to try this bc I have so many scraps. My grandmaw gave me 4 big boxes of fabric and scraps. I'm wondering does it have to be all the same material? I'm mainly using cotton. But you know there's the material I buy and it seems kinda hard, and then there's the kind a shirt is made out of, and it says 100% cotton but is so soft. Whats the difference? And can I use these 2? I have lots of old shirts I'd like to use, but they are alot softer than the other material. Does that make sense?