Wet the wire brush (not the wooden sanding block) and shake off the excess water.
Make circular brushing on the loaded sandpaper. Wipe off the crud.
You can extend the life of your sandpaper three or four times!
This is the four sided fingernail file sold at beauty supply stores.
It's great for shaping fin tapers.
It's also washable so you can remove any buildup with the soft brass brush shown above.
Tack cloths (especially when new) can leave a sticky, oily covering on your model.
I use a brush to remove any dirt or sanding sawdust before any finishing.
That cheap 1" wide utility brush is also used for brushing on the thinned CWF.
They are under $1.00 at Home Depot.