Normally without much change to the shade or colour, Le Tonkinois
will adhere well to properly prepared existing varnish and paint
finishes. Use 220 grit paper for a good 'key'. Wood previously
treated with wax products cannot be treated directly, but see "Wooden
floors and parquet".
Where the existing varnish is to be removed, chemical
products should be avoided, to ensure that remnants do not reduce the
efficiency of the Le Tonkinois. If such products are used, please
follow the directions for use closely.