Toneman,
Glade to hear that your making saw dust now, lol those areas your talking about are in my way of thinking pine knots or where the pine sap or tar as i know it has harden, if you can next time smell it and you should smell a likeable smell like cedar some what,
I like you will learn more and more about this scrollsaw and how it works and limits as we do more with them, slow yet steady pressure is what you need to do it and then before you know it you'll be flying through these things and thinking who of thought it, lol
Have a good one, just wanted to see if you got it figured out, so I could learn more from you,
Poppa Rob