If you keep track of what you put in the machine in the first place you won't have to try and figure out what it is when you take it out.
I have a craft box from JoAnn's that's just the right size for needle packages. The orange button is for the Janome and the dark red button is for the Pfaff. I put the button in the compartment of the needle I take out and put in the machine. Any loose needle in a compartment has been used but is still good.
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