Dennis,
That suggestion had been made a few years ago in that magazine and was met with letter after letter criticizing the technique. I'm surprised they repeated it. Any sprayed on finish, while maybe looking nice and shiny at first, will not be true to the original appearance. Many of us prefer that original finish.
But, if you like that appearance, by all means, do what you like best. But, it will definitely make a huge difference in future value for really collectible pieces if that is of any concern to you.
Warm water, mild dish soap and maybe a soft toothbrush have been the tried and true cleaning methods. Even at that, avoid soaking or rubbing the lettering as some is water soluble. Blot carefully with a soft cloth around lettering.
Jim
