.... she asked if I knew of a good way to clean or brighten up the paneling in her
kitchen and dining room. ....
.... it has darkened considerably over the years. *Because of waxing, cooking, or cigarette smoke I've no
idea. *I suspect all of the above, and maybe more.
The only thing I can think of offhand is TSP.
I would not use TSP - it, essentially, dissolves oils.
First, try the least aggressive method. I recommend Murphy's Oil Soap:
http://www.colgate.com/MurphyOilSoap...iginal-formula
We've been using this for a long time.