This truly is the secret French polishers don't want you to know!
Although French polish is undoubtably still the most beautiful finish that can be applied to wood, it has the distinct disadvantage of being very vulnerable to heat damage. Hot mugs and plates left on a French polished surface will undoubtably leave a white mark where the constituent shellac has been melted.
The following method is a first line course of action with the potential to save you from having to pay for an expensive re-polishing. I cannot guarantee it will work in all cases, since it depends on the level of heat damage to the piece. If the wood underneath has been burned, you will certainly need to go to a professional.
This will only work on true French polish - don't try it on laquers or varnishes. To find out whether it is french polish rub a little methylated spirit on a small unshowing area of the piece with a rag. Now feel it; if it is tacky it's french polish, if not, it's laquer or varnish.
You will need:
- Soft rags - think pyjama material.
- Abrasive cleaner such as T-cut or Brasso (T-cut if possible - I find it leaves less residue).
- Fine steel wool - known as either 0000 or Superfine.
- Beeswax or similar furniture wax.
- Make sure the area is clean and free of residue such as wax or furniture polish.
- Put a little T-cut on the rag and rub in a circular motion over the white heat mark - you'll need to do this vigorously and for a minute or so, or until you can see the mark disappear.
- When the mark has gone, look at the whole piece in back-lighting. You will probably find that the area you have just rubbed is far more glossy than the rest of the surface. Don't panic! Scoop up a little wax on a pad of wire wool. Now gently but firmly rub the wax into the the surface in the direction of the wood grain. Concentrate a little more on the area you have just treated and make sure the whole piece comes up to a uniform sheen.
- Leave the wax on the piece for around 5 minutes then, with a clean piece of rag, buff firmly across the piece in the direction of the grain and, hey presto, you should have a beautifully revived piece!
- Alternatively, if you wish to bring the entire surface up to a mirror-like finish, you can use the T-cut to burnish the piece. Go gently and steadily though - T-cut is an abrasive and will cut through the polish, so you want to use as little as possible. To finish, buff the surface with a clean rag.