Short of refinishing, Howard Restore a Finish works very well, even on finishes with minor blotches and scratches. Then a Wipe-on poly or simple Minwax over that if desred. If you simply want to feed/shine the current wood/finish, Wood Preen is good.
They have a product called "restore a finish" if the stain is bad. The also have "feed and wax" to feed and restore dry wood.
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