They get everywhere. They just do. If you think you see a skinny mineral with an exciting squiggly habit, you’re really seeing a rogue bit of paper towel or someone’s T-shirt or something. If it’s blue in PPL, you’re looking at a bit of shop towel. Why, yes! Your friendly author has used shop towels in making thin sections! It didn’t work out all that well and she doesn’t recommend it.
Here’s a protip for you: when making a thin section, if you need to wipe your slide and/or cover slip clean and you don’t have any Kimwipes, dampen a white paper coffee filter with isopropyl alcohol and wipe gently until the little glass thing sparkles. White paper coffee filters are great at not leaving rogue fibers all over the place, and isopropyl alcohol removes all manner of stickiness.