Prep for older dulcimer before refinish

What a great place for information! I made a dulcimer with Keith Young years ago and never got the finish right. In a not-so-bright attempt to clean it years later, I used a spray cleaner for dusting it. I would like to give it a coat or two of a real finish but need to know what I should use first to clean and prep the wood before using finish. Also, any thoughts on Minwax? Thanks for the sage advice.