Now, wet your pad with alcohol. Sprinkle on the rotten stone—onto the pad, not the piano—and rub it with your finger, so it’s well spread and forms a transparent layer. Now press the pad onto the piano and rub in clockwise circles.
And rub. And rub some more. This might be where you want to find the teenager and that drink.
If you get too much pumice in any area, add more alcohol and work it to another area that might need more pumice.
Now, either get a new pad, or apply a new cover to your pad. Used T-shirts would do. I would prefer a new pad with a cover of used T-shirts, but your mileage may vary.
Take your heavier mix of shellac, now, and load your pad, then put a few drops of alcohol on your pad. Then a drop of olive oil. Just wet your finger with olive oil and rub on pad. Now, smack the pad against your GLOVED hand to distribute the shellac. You need the pad loaded, but not too loaded. Kind of like the state you should achieve while watching the teen do this.
Glide the pad onto the surface of the piano, working on a little area at a time to prevent its sticking. Do not stop. Or at least, do not stop with the pad on the piano.
After you’re done with a portion of the piano, remove the excess oil by running a pad with just a little bit of shellac and a few drops of alcohol all over the section.
Let the whole thing rest for a couple of hours. No, you don’t get to rest. You start on another section.
Repeat until the result is pleasing to the eye; the teen, if you’re employing one, falls down of tiredness; and/or you’re too sloshed, if you’ve been loading yourself as well as the pad, to see whether the surface looks right.
At this point it is a good time to get hold of your piano-knowing friend and get him to do the totally inconsequential work of getting the piano to play. Failing that, you can also pay a professional to do it, though it will probably be pricier than a new piano.
French polish can also be used for other pieces of furniture such as sideboards and tables, though I have no idea why you’d do it unless you’re in the habit of playing your dining room table.
If so, by all means, carry on.