How are the wood floors finished?
If they are polyurethaned, then I would probably use a mild soap solution or a mild vinegar and water solution. Polyurethane pretty much protects against any kind of non-abrasive cleaner.
If these are newer floors that might not be polyurethaned, she should use only the cleaner recommended by the flooring company. Flooring finishes not protected by polyurethane can be damaged by some cleaners.
Starch is water-soluble, so plain water should work too.