That's a useful video. More on that in a minute.
That looks like a Scotchbrite "no scratch" pad made for teflon/ no stick pans. It's made out of some sort of mineral fiber.
I've never tried that, my only concern would be scratching. Resin comes in all kinds of hardnesses, as does plastic. Where he uses it is to get into crevasses in that oxygen hose type of part. I'd be really careful on otherwise smooth surfaces.
Other comments. The modeler is pretty oblivious to dust control. Resin dust is an irritant and you do not want to breath it. Esp. if you use the tool he refers to but doesn't use, a belt sander. I don't think you need to wear a mask, but working on a surface that can be folded up and tipped into a garbage bag, and sweeping up after, are important.
His tools that figure most are the little razor saw, the Xacto, sanding sticks and sand paper.
The saw and the Xacto are self explanatory.
I get those sanding sticks in the cosmetics section at CVS. They can be cut into smaller pieces or have their edges renewed.
For sanding, one thing I would add is to tape it down on a very flat surface. Draw sand the part over that, don't rub them together loosely.
Now, he just solved a problem of filling a gap that I've been struggling with, using plastic card.
Thanks for posting that.