I got to thinking about tea tree oil and did some reading. Applied topically it is considered to be anti-viral, anti-bacterial, and anti-fungal. Prevents transmission of MRSA.
"Mix 14 ounces of water with 1 ounce of Murphy's oil soap and 10 drops of tea tree oil. Use an old spray bottle that has been cleaned thoroughly, and then mark the outside of the spray bottle with "Tea Tree Oil Cleaner" or with a similar name."
Constant use is not good for wood, but if you use it occasionally it will impart the anti-septic properties of tea tree oil to the wood.