I use the cores of duct tape or clear tape for a strong base for pin cushions.
They last forever, are cheap and you can make some of the cutest styles
with them.
For cleaning out sewing machines, I use a curved eyelash brush..it also
works for the keyboards! Especially since I have a very long haired Persian
cat who loves to wander in front of my computer and wave her brush of a tail
around, leaving drifting snow of cat hairs behind her!!