Bobbins - which are which
I'm cleaning, I know, I know, weird huh!! But am finding lots of bobbins all over the place. I know you need certain bobbins for certain machines. But how do you tell which are which once they are away from the packaging? I have metal and plastic. Some with lots of round holes, some with a little square hole and some with a ribbed/rough top and bottom??????? Which is which and which are for what?? Is there a chart?