: What do I use to wipe off all the sanding dust before I varnish? I wanna make
: sure I don't use something that's gonna leave a film on the surface that
: could prevent the varnish from sticking or curing.

If you are using standard varnish a tack cloth works well. First vacuum off the worst dust. Then wash it with water. Whatever is left can be cleaned off with a tack cloth. An old T-shirt soaked in thinner also works well. But if you use softener or anti-cling sheets in your drier you should not use your old T-shirts. The drier sheets may introduce contaminants that will be desolved by the thinner. You can also use white paper towels.