I dont think it would be useful as a method of chelation. After taking copious amounts of garlic over the last few years and having done a hair mineral analysis recently it still shows high levels of mercury.
I have been swallowing a pierced fresh clove of garlic regularly as a remedy for killing bacteria overgrowth, candida, as an Antibiotic during flu or colds. Garlic is also very good for the heart and circulation though buddhist apparently don't eat it because it can increase excitement supposedly.
If you were to use garlic I'd warn you that if you have high levels of stomach acid or any gastritis condition it can irritate the stomach.