Sand your wood thoroughly with medium grit sandpaper. Remove all traces of paint or varnish so you are left with only the bare wood. Previously unpainted pieces do not require sanding. Wipe away any sanding dust with a damp rag.
Mix whiting into your pickling stain according to the package directions. Whiting will fill in the pores of the wood and provide a more consistent finish.
Dip a rag into the pickling mixture and rub it into the wood. Wipe away the excess with a clean rag. Continue applying and rubbing off excess stain until the wood is uniformly covered. Allow the stain to dry.
Mix two parts denatured alcohol with five parts clear shellac. Shellac will protect the finish without yellowing.
Brush on the shellac mixture in a thin coat. Let the shellac dry. Sand the wood lightly with fine grit sandpaper. Wipe off any sanding dust. Apply a second coat of shellac.