You should be able to lightly sand the raised wood, and coat with finish. I would try this in an area that may not be too noticable first. Finish if applied properly should last for many many years. Water on the finish should have no effect. I use a catalyzed Varnish and part of the test is 30 days wet in a bell jar with no effect. Lacquer is softer and will allow water to penetrate the finish, this is what causes the white ring when a glass is left on a piece of furniture. The water will evaporate but the minerals left behind form the ring. Kitchen cabinets typically are coated with a Catalyzed finish of some type as it is much more reistant to water. Were these cabinets finished on the job ? You can also take a drawer head and sand and recover the inside to make sure the new finish is compatable with the existing finish, that way if there is a problem it will not show.

Good Luck !

Tom999
Thanks for the information. I suspect that the kitchen cabinets were finished before they were installed, but I'm not so sure about the bathroom vanity and the window seats. The fact that a can of polyurethane was left on-site makes me suspect that at least some of the finish work was done after installation. I'm having the least trouble in the kitchen and the most trouble on the window seats (which only have moist air around them, not water spilled on them(?)) So I can apply the catalyzed varnish directly over the poly? Do you have a particular brand you use?

I wish I had known about these forums when I had the work done - would have had a lot better installation for a lot less money!

Thanks again.

Try Sherwin Williams they can help you . They can also test your existing finish to see if it is compatable.
Good luck !