You may find that the varnish may cause the ink to smudge. Try using heat gun ( hair dryer) to soften the blob and a scraper or putty knife to reduce it.

I second the heat gun approach.  It worked for me.

Thanks guys.  You have affirmed my fears about what the solvent in varnish might do to Sharpie ink.  I was hoping to find someone who had tried it successfully.

 These spots were small.  It seemed like a heat gun would cause too much collateral damage.  I drilled them out with a dental burr on a dremel and filled the depressions with epoxy/flour.  Good as new.  

Thanks again for your input.

Hooper