One person posted they are using up old thread. The shop owner where I bought my new Viking stated that any thread on a wooden or styrofoam spool should be discarded as being too old. That eliminated a lot of spools from my stash. I know I've had some of those around for 30 yrs. It all went in the trash. I use 50 wt. natural color thread on a large cone which I buy from the same shop. It works well on my machine. JCY