Hi Mike...I use borax or sodium tetraborate in my own anti-candida protocol. Borax is perhaps the ultimate fungal killer. It also removes fluorine from the body as well as kills mycoplasma and myccobacteria(which is the main cause of arthritis).
I've been using and supplementing borax for 8 years and that's how I know its very safe. In the Material Safety Data Sheet(MSDS) -- which is the toxicity and handlling bible for all research -- borax has the same toxicity profile as common table salt.
I currently take borax as an anti-fungal, arthritic preventaitive and fluorine detoxer a few times a week in my coffee. I use it like a pinch of salt in my coffee. Keeps the mycolasma, fungus etc out of my body. I'm 65 yo with nothing wrong with me now. Healthy as a lamb.
I would not use borax in cooking because it is fairly alkaline and might adversely effect your stomach acid digestion but you can use the borax water in other drinks like teas and your coffee.
The borax regimen I successfully followed to get rid of my systemic candida problem included higher dose borax -- 1/4 tspn(1000 mgs) borax in a liter of water to be drunk slowly throughout the whole day. Women should only take 1/8 tspn dose per day. Take this borax water for 4 days on then take 3 days off in a continuous rolling protocol like that.
Ignore the smell and stop letting your unreasonable fears rule common sense. My borax is 6 years old and it stinks as you describe. But hey, it was one of the main protocols that helped to destroy and cure my own systemic candida problems 8 yrs ago. My candida is defeated and entirely gone and has never returned in 8 yrs. I still supplement the stinking borax and have tremendous respect for it, so get over your unreasonable fears, my friend, or you wont cure anything. See this link for more info on Borax. My anti-candida protocol is here.