Apparently there is not a lot of info online about this. I only found this bit below.
• White Vinegar – Almost the most natural substance you can find, white vinegar is both cheap and highly effective. The active ingredient is acetic acid. Acids neutralize alkaline substances such as hard water scale and dissolve gummy build up, eat away tarnish and remove dirt from wood surfaces. Vinegar is also a fantastic glass and window cleaner.
We heard that vinegar will also kill poison ivy, but didn’t believe it. We were proven wrong last year. Not only does it work, it works great!
Could you maybe call a furniture store or a home steam cleaning service for some guidance? Or a local extension agent- you can find one near you at this link. http://www.csrees.usda.gov/Extension/