Vinegar kills bacteria on contact, but I don't know anything about grapeseed oil.
I've seen a lot of places where they say to clean off the dirt and muck first and then spray vinegar on a surface and let it dry with it on. Either way, vinegar is good stuff (the acetic acid in vinegar is intolerable to most molds and bacteria). Tea tree oil is the same way.http://vinegar.faithweb.com/about.html
Disinfect with Vinegar
The disinfectant properties of vinegar have been verified by numerous studies including those conducted by the Good Housekeeping Institute, as reported on 48 hours (on CBS) in 2000. A straight 5% solution of vinegar kills 99 percent of bacteria, 82 percent of mold, and 80 percent of viruses, however in the USA, it cannot be declare a disinfectant without registering it as a pesticide with the EPA. Having said that, mix distilled white vinegar (found in any supermarket) with water and keep spray bottles of this non-toxic disinfectant in your bathrooms and kitchen - to disinfect and clean.