Spray the wood panels with an all-purpose wood cleanser. Wipe them down with a lint-free cloth. Allow them to air dry.
Place a piece of 100-grit sandpaper at the bottom of an electric sander. Sand the oak panels, covering all of the surface area. Repeat with 220-grit sandpaper and 360-grit sandpaper.
Wipe down the panels with a tack cloth to get rid of all the dust from sanding. Pour the varnish of your choice into a paint tray. Dip a paint roller in it and cover the wall with a light coat of varnish.
Allow the varnish to dry overnight. Sand it with a sheet of 800-grit sandpaper to bring the oak to a glossy shine. Wipe it down with a tack cloth and then apply a final coat of varnish, allowing it to dry overnight.