Zep Fast 505 is my magic bullet for tobacco tar.
I work part time at a cigar shop, and we smoke inside.
A lot. Imagine the size of an average cigar compared to a cigarette. Imagine 5-20 people smoking said cigars in an inclosed 900sq. Ft. space (with excellent air filtration, of my own personal design. Getting my coworkers and my cheapskate boss to remember to turn it on is another story, ugh) for 5-12 hours a day, Seven days a week. This is my reality. I know tar. Fast 505 works. I use it to clean everything from UAS Smokeeter air purifier collection cells to painted walls, to furniture, light fixtures, and interior woodwork. It
MELTS tobacco tar on contact. You can get it at Home Depot. It smells like Lemon and isn't noxious or toxic. All you need to do is spray it on the nicotine coated surface, wait 30 seconds to a minute, and wipe it off. To be safe, Try it on a small, inconspicuous area first to make sure it doesn't react with the finish. I haven't had any problem with finished wood surfaces, personally. Just don't leave it on too long and you'll be fine.
http://www.zepcommercial.com/product...-and-Degreaser
Oven cleaner is extremely corrosive, and contains lye. It attacks Aluminum and Steel with a vengeance. I could only imagine what it does to wood finishes. I had to throw out a set of aluminum smokeeter collection cells because my boss repeatedly cleaned them with Easy-off and corroded them to all hell.